> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt # MongoDB Server Parameters for a Self-Managed Deployment **Note:** Starting in MongoDB 8.0, LDAP authentication and authorization is deprecated. LDAP is available and will continue to operate without changes throughout the lifetime of MongoDB 8. LDAP will be removed in a future major release. For details, see [LDAP Deprecation.](https://www.mongodb.com/docs/manual/core/LDAP-deprecation.md#std-label-ldap-deprecation) ## Synopsis MongoDB provides several configuration options that you can set using: - the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, : } ) ``` - the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) configuration setting: ```yaml setParameter: : ... ``` - the `--setParameter` command-line option for [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--setParameter) and [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-option-mongos.--setParameter) ```bash mongod --setParameter = mongos --setParameter = ``` For additional configuration options, see [Self-Managed Configuration File Options](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options), [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) and [`mongos`.](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ## Parameters ### Authentication Parameters [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: true Allows or disallows the retrieval of authorization roles from client X.509 certificates. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `MONGODB-X509,SCRAM-SHA-1,SCRAM-SHA-256` Starting in MongoDB 8.3, if [`mongod --tlsFIPSMode`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsFIPSMode) or [`mongos --tlsFIPSMode`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-option-mongos.--tlsFIPSMode) is enabled, `SCRAM-SHA-1` is excluded from the effective default. Specifies the list of authentication mechanisms the server accepts. Set this to one or more of the following values. If you specify multiple values, use a comma-separated list and no spaces. For descriptions of the authentication mechanisms, see [Authentication on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/authentication.md) | Value | Description | | --- | --- | | [SCRAM-SHA-1](https://www.mongodb.com/docs/manual/core/security-scram.md#std-label-authentication-scram-sha-1) | [RFC 5802](https://tools.ietf.org/html/rfc5802) standard Salted Challenge Response Authentication Mechanism using the SHA-1 hash function. | | [SCRAM-SHA-256](https://www.mongodb.com/docs/manual/core/security-scram.md#std-label-authentication-scram-sha-256) | [RFC 7677](https://tools.ietf.org/html/rfc7677) standard Salted Challenge Response Authentication Mechanism using the SHA-256 hash function. | | [MONGODB-X509](https://www.mongodb.com/docs/manual/core/security-x.509.md#std-label-security-auth-x509) | MongoDB TLS/SSL certificate authentication. | | [GSSAPI](https://www.mongodb.com/docs/manual/core/authentication.md#std-label-security-auth-kerberos) (Kerberos) | External authentication using Kerberos. This mechanism is available only in [MongoDB Enterprise](http://www.mongodb.com/products/mongodb-enterprise-advanced). | | [PLAIN](https://www.mongodb.com/docs/manual/core/authentication.md#std-label-security-auth-ldap) (LDAP SASL) | External authentication using LDAP. You can also use `PLAIN` for authenticating in-database users. `PLAIN` transmits passwords in plain text. This mechanism is available only in [MongoDB Enterprise](http://www.mongodb.com/products/mongodb-enterprise-advanced). | | [MONGODB-OIDC](https://www.mongodb.com/docs/manual/core/oidc/security-oidc.md#std-label-authentication-oidc) | OpenID Connect is an authentication layer built on top of OAuth2. This mechanism is available only in [MongoDB Enterprise](http://www.mongodb.com/products/mongodb-enterprise-advanced). | Starting in MongoDB 8.3, you cannot specify `SCRAM-SHA-1` for [`authenticationMechanisms`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.authenticationMechanisms) while also specifying [`mongod --tlsFIPSMode`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsFIPSMode) or [`mongos --tlsFIPSMode`.](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-option-mongos.--tlsFIPSMode) If you try to specify `SCRAM-SHA-1` for `authenticationMechanisms` while also specifying `--tlsFIPSMode`, the server throws an error and logs a message similar to the following: ```none SCRAM-SHA-1 is not allowed in FIPS mode. ``` This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to specify both `PLAIN` and `SCRAM-SHA-256` as the authentication mechanisms, use the following command: ```bash mongod --setParameter authenticationMechanisms=PLAIN,SCRAM-SHA-256 --auth ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 0 **Note: Enterprise Feature** Available in MongoDB Enterprise only. The number of milliseconds to wait before informing clients that their authentication attempt has failed. This parameter may be in the range `0` to `5000`, inclusive. Setting this parameter makes brute-force login attacks on a database more time-consuming. However, clients waiting for a response from the MongoDB server still consume server resources, and this may adversely impact benign login attempts if the server is denying access to many other clients simultaneously. **Changed in version 7.0** (Also starting in 6.0.7 and 5.0.18) In previous versions, AWS IAM authentication retried only when the server returned an HTTP 500 error. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 2 For MongoDB deployments using [AWS IAM credentials](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html) or [AWS IAM environment variables.](https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-envvars.html#envvars-list) Maximum number of AWS IAM authentication retries after a connection failure. The following example sets [`awsSTSRetryCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.awsSTSRetryCount) to `15` retries: ```bash mongod --setParameter awsSTSRetryCount=15 ``` Alternatively, the following examples uses the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, awsSTSRetryCount: 15 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Set the [`clusterAuthMode`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.clusterAuthMode) to either `sendX509` or `x509`. Useful during [rolling upgrade to use x509 for membership authentication](https://www.mongodb.com/docs/manual/tutorial/upgrade-keyfile-to-x509.md#std-label-upgrade-to-x509-internal-authentication) to minimize downtime. For more information about TLS/SSL and MongoDB, see [Configure MongoDB Instances for TLS/SSL Encryption](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md) and [TLS/SSL Configuration for Clients](https://www.mongodb.com/docs/manual/tutorial/configure-ssl-clients.md) . This parameter is only available at runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. ```bash db.adminCommand( { setParameter: 1, clusterAuthMode: "sendX509" } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `true` Specify `0` or `false` to disable localhost authentication bypass. Enabled by default. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. See [Localhost Exception in Self-Managed Deployments](https://www.mongodb.com/docs/manual/core/localhost-exception.md#std-label-localhost-exception) for more information. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Set to `false` to disable the `O/OU/DC` check when `clusterAuthMode` is `keyFile` in your configuration file. This allows clients possessing member certificates to authenticate as users stored in the `$external` database. The server won't start if `clusterAuthMode` isn't `keyFile` in your configuration file. To set the `enforceUserClusterSeparation` parameter to `false`, run the following command during startup: ```javascript mongod --setParameter enforceUserClusterSeparation=false ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 60 seconds (1 minute) Specifies the minimum time period that must pass between subsequent fetches of a given IdP's `JWKSetURI` endpoint. If an RSA public key is changed multiple times within the quiesce period, that key may not work as expected for up to a minute unless the quiesce period is manually reduced. If this parameter is set to zero, there is no quiesce period and the key can be refreshed repeatedly. This parameter is available at both startup and runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 7776000 seconds (90 days) Specifies the number of seconds for which an [HMAC signing key](https://en.wikipedia.org/wiki/Hash-based_message_authentication_code) is valid before rotating to the next one. This parameter is intended primarily to facilitate authentication testing. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 60000 The number of milliseconds in-between health checks of the pooled LDAP connections. You can only set [`ldapConnectionPoolHostRefreshIntervalMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolHostRefreshIntervalMillis) during start-up, and cannot change this setting with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 300 The maximum number of seconds that the pooled connections to an LDAP server can remain idle before being closed. You can only set [`ldapConnectionPoolIdleHostTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolIdleHostTimeoutSecs) during start-up, and cannot change this setting with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Changed starting in MongoDB versions 5.0.9 and 6.0.0* Changed default value to `2`. In previous versions, the default is unset. *Default*: 2 The maximum number of in-progress connect operations to each LDAP server. You can only set [`ldapConnectionPoolMaximumConnectionsInProgressPerHost`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolMaximumConnectionsInProgressPerHost) during start-up, and cannot change this setting with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Changed starting in MongoDB versions 5.0.9 and 6.0.0* Changed default value to `2147483647`. In previous versions, the default is unset. *Default*: 2147483647 The maximum number of connections to keep open to each LDAP server. You can only set [`ldapConnectionPoolMaximumConnectionsPerHost`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolMaximumConnectionsPerHost) during start-up, and cannot change this setting during run time with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 1 The minimum number of connections to keep open to each LDAP server. You can only set [`ldapConnectionPoolMinimumConnectionsPerHost`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolMinimumConnectionsPerHost) during start-up, and cannot change this setting during run time with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: true A boolean that determines whether the LDAP connection pool (see [`ldapUseConnectionPool`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUseConnectionPool)) should use latency of the LDAP servers to determine the connection order (from lowest latency to highest). You can only set [`ldapConnectionPoolUseLatencyForHostPriority`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapConnectionPoolUseLatencyForHostPriority) during start-up, and cannot change this setting during run time with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: false Enables the performance of concurrent LDAP operations. **Note:** Only if you are certain that your instance of `libldap` is safe to use in this mode, enable this flag. You may experience crashes of the MongoDB process if the `libldap` version you are using is not thread safe. You must use [`ldapForceMultiThreadMode`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapForceMultiThreadMode) to use LDAP connection pool. To enable LDAP connection pool, set [`ldapForceMultiThreadMode`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapForceMultiThreadMode) and [`ldapUseConnectionPool`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUseConnectionPool) to `true`. **Tip:** If you have any concerns regarding your MongoDB version, OS version, or libldap version, contact MongoDB Support. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: string The password used to bind to an LDAP server. You must use [`ldapQueryUser`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapQueryUser) with this parameter. If not set, mongod or mongos does not attempt to bind to the LDAP server. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: string The user that binds to an LDAP server. You must use [`ldapQueryPassword`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapQueryPassword) with this parameter. If not set, mongod or mongos does not attempt to bind to the LDAP server. **New in version 6.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 0 For MongoDB deployments using [LDAP Authorization on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/security-ldap-external.md#std-label-security-ldap-external) Number of operation retries by the server LDAP manager after a network error. For example, the following sets [`ldapRetryCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapRetryCount) to `3` seconds: ```bash mongod --ldapRetryCount=3 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, ldapRetryCount: 3 } ) ``` **New in version 5.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true For MongoDB deployments using [LDAP Authorization on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/security-ldap-external.md#std-label-security-ldap-external) Starting in MongoDB 5.2, the update interval for cached user information retrieved from an LDAP server depends on [`ldapShouldRefreshUserCacheEntries`:](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapShouldRefreshUserCacheEntries) - If true, use [`ldapUserCacheRefreshInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheRefreshInterval) - If false, use [`ldapUserCacheInvalidationInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheInvalidationInterval) You can only set [`ldapShouldRefreshUserCacheEntries`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapShouldRefreshUserCacheEntries) during startup in the [`configuration file`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) or with the `--setParameter` option on the command line. For example, the following disables [`ldapShouldRefreshUserCacheEntries`:](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapShouldRefreshUserCacheEntries) ```bash mongod --setParameter ldapShouldRefreshUserCacheEntries=false ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Specifies whether MongoDB should use connection pooling when connecting to the LDAP server for authentication/authorization. MongoDB uses the following default values: - true on Windows. - true on Linux where MongoDB Enterprise binaries are linked against `libldap_r`. - false on Linux where MongoDB Enterprise binaries are linked against `libldap`. You can only set [`ldapUseConnectionPool`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUseConnectionPool) during start-up, and cannot change this setting with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) database command. **Changed in version 5.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 30 seconds **Note:** Starting in MongoDB 5.2, the update interval for cached user information retrieved from an LDAP server depends on [`ldapShouldRefreshUserCacheEntries`:](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapShouldRefreshUserCacheEntries) - If true, use [`ldapUserCacheRefreshInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheRefreshInterval) - If false, use [`ldapUserCacheInvalidationInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheInvalidationInterval) For use with MongoDB deployments using [LDAP Authorization on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/security-ldap-external.md#std-label-security-ldap-external) The interval (in seconds) that the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance waits between external user cache flushes. After MongoDB flushes the external user cache, MongoDB reacquires authorization data from the LDAP server the next time an LDAP-authorized user issues an operation. Increasing the value specified increases the amount of time MongoDB and the LDAP server can be out of sync, but reduces the load on the LDAP server. Conversely, decreasing the value specified decreases the time MongoDB and the LDAP server can be out of sync while increasing the load on the LDAP server. **New in version 5.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 30 seconds **Note:** Starting in MongoDB 5.2, the update interval for cached user information retrieved from an LDAP server depends on [`ldapShouldRefreshUserCacheEntries`:](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapShouldRefreshUserCacheEntries) - If true, use [`ldapUserCacheRefreshInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheRefreshInterval) - If false, use [`ldapUserCacheInvalidationInterval`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheInvalidationInterval) For MongoDB deployments using [LDAP Authorization on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/security-ldap-external.md#std-label-security-ldap-external) The interval in seconds that [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) waits before refreshing the cached user information from the LDAP server. The maximum interval is 86,400 seconds (24 hours). For example, the following sets [`ldapUserCacheRefreshInterval`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheRefreshInterval) to `4000` seconds: ```bash mongod --setParameter ldapUserCacheRefreshInterval=4000 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, ldapUserCacheRefreshInterval: 4000 } ) ``` **New in version 5.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 90 seconds For MongoDB deployments using [LDAP Authorization on Self-Managed Deployments.](https://www.mongodb.com/docs/manual/core/security-ldap-external.md#std-label-security-ldap-external) The interval in seconds that [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) retains the cached LDAP user information after the last cache refresh. If more than [`ldapUserCacheStalenessInterval`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheStalenessInterval) seconds elapse without a successful refresh of the user information from the LDAP server, then [`mongod`:](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) - Invalidates the cached LDAP user information. - Is unable to authenticate new sessions for LDAP users until [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) connects to the LDAP server and authorizes the LDAP user. - Authorizes any existing sessions that use previously authenticated LDAP users if [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) is unable to connect to the LDAP server. When [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) reconnects to the LDAP server, [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) ensures the LDAP users are correctly authorized. The maximum interval is 86,400 seconds (24 hours). For example, the following sets [`ldapUserCacheStalenessInterval`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ldapUserCacheStalenessInterval) to `4000` seconds: ```bash mongod --setParameter ldapUserCacheStalenessInterval=4000 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, ldapUserCacheStalenessInterval: 4000 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 5.0** *Default*: 200 The maximum memory usage limit in megabytes for the [`validate`](https://www.mongodb.com/docs/manual/reference/command/validate.md#mongodb-dbcommand-dbcmd.validate) command. If the limit is exceeded, [`validate`](https://www.mongodb.com/docs/manual/reference/command/validate.md#mongodb-dbcommand-dbcmd.validate) returns as many results as possible and warns that not all corruption might be reported because of the limit. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Available on Linux and macOS. *Default*: true The flag that enables or disables OCSP. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following disables OCSP: ```bash mongod --setParameter ocspEnabled=false ... ``` Starting in MongoDB 6.0, if [`ocspEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspEnabled) is set to `true` during initial sync, all nodes must be able to reach the [OCSP](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md#std-label-ocsp-support) responder. If a member fails in the [`STARTUP2`](https://www.mongodb.com/docs/manual/reference/replica-states.md#mongodb-replstate-replstate.STARTUP2) state, set [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) to a value that is less than `5`. **See also:** - [`ocspStaplingRefreshPeriodSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspStaplingRefreshPeriodSecs) - [`tlsOCSPStaplingTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPStaplingTimeoutSecs) - [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Available on Linux. The number of seconds to wait before refreshing the stapled OCSP status response. Specify a number greater than or equal to 1. You can only set [`ocspStaplingRefreshPeriodSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspStaplingRefreshPeriodSecs) during startup in the [`configuration file`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) or with the `--setParameter` option on the command line. For example, the following sets the parameter to 3600 seconds: ```bash mongod --setParameter ocspStaplingRefreshPeriodSecs=3600 ... ``` Starting in MongoDB 5.0, the [`rotateCertificates`](https://www.mongodb.com/docs/manual/reference/command/rotateCertificates.md#mongodb-dbcommand-dbcmd.rotateCertificates) command and [`db.rotateCertificates()`](https://www.mongodb.com/docs/manual/reference/method/db.rotateCertificates.md#mongodb-method-db.rotateCertificates) method will also refresh any stapled OCSP responses. **See also:** - [`ocspEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspEnabled) - [`tlsOCSPStaplingTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPStaplingTimeoutSecs) - [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **Changed in version 8.0** (*Also available in 7.3 and 7.0*) Use this parameter to specify IdP (Identity Provider) configurations when using [OpenID Connect Authentication.](https://www.mongodb.com/docs/manual/core/oidc/security-oidc.md#std-label-authentication-oidc) `oidcIdentityProviders` accepts an array of zero or more IdP configurations. An empty array (default) indicates no OpenID Connect support is enabled. When more than one IdP is defined, `oidcIdentityProviders` uses the `matchPattern` field to select an IdP. Array order determines the priority and the first IdP is always selected. Starting in MongoDB 8.0, when multiple IdPs are defined, the [`oidcIdentityProviders`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.oidcIdentityProviders) parameter accepts duplicate `issuer` values as long as the `audience` value is unique for each issuer. This is also available in versions 7.3 and 7.0. #### oidcIdentityProviders Fields | Field | Necessity | Type | Description | | --- | --- | --- | --- | | `issuer` | Required | string | The issuer URI of the IdP (Identity Provider) that the server should accept tokens from. This must match the `iss` field in any JWT used for authentication. Starting in MongoDB 8.0, when multiple IdPs are defined, the [`oidcIdentityProviders`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.oidcIdentityProviders) parameter accepts duplicate `issuer` values as long as the `audience` value is unique for each issuer. This is also available in versions 7.3 and 7.0. If you specify an unreachable issuer URI, MongoDB: Logs a warning.; Continues server startup, which allows you to update the issuer URI.; Reattempts issuer contact. If MongoDB reaches the issuer URI and validates the access token, authentication succeeds. If the issuer URI remains unreachable, authentication fails. **Changed in version 8.0** (*Also available in 7.3 and 7.0*) | | `authNamePrefix` | Required | string | Unique prefix applied to each generated `UserName` and `RoleName` used in authorization. `authNamePrefix` can only contain the following characters: alphanumeric characters (combination of `a` to `z` and `0` to `9`); hyphens (`-`); underscores (`_`) | | `matchPattern` | Conditional | string | Regex pattern used to determine which IdP should be used. `matchPattern` matches against usernames. Array order determines the priority and the first IdP is always selected. `matchPattern` is required in some configurations, depending on how the user sets `supportsHumanFlows`: When only one IdP has `supportsHumanFlows` set to `true` (the default), `matchPatterns` is optional.; When multiple IdP's have `supportsHumanFlows` set to `true` (the default), each of these requires `matchPatterns`.; `matchPatterns` is optional for any IdP where `supportsHumanFlows` is set to `false`. This is not a security mechanism. `matchPattern` serves only as an advisory to clients. MongoDB accepts tokens issued by the IdP whose principal names do not match this pattern. | | `clientId` | Conditional | string | ID provided by the IdP to identify the client that receives the access tokens. Required when `supportsHumanFlows` is set to `true` (the default). | | `audience` | Required | string | Specifies the application or service that the access token is intended for. Starting in MongoDB 7.0, only one `audience` oidcIdentityProviders field can be specified for OIDC access tokens. `audience` fields with empty arrays or arrays of multiple strings are invalid. When more than one IdP is defined, this must be a unique value for each configuration that shares an `issuer`. | | `requestScopes` | Optional | array[ string ] | Permissions and access levels that MongoDB requests from the IdP. IMPORTANT: By default, clients such as [Compass](https://www.mongodb.com/docs/compass/current/) and [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) request the `oidc` and `offline_access` scopes from the IdP. If the IdP supports neither `oidc` nor `offline_access`, the client doesn't request them. If the IdP supports `oidc` but not `offline_access`, you must re-authenticate frequently. | | `principalName` | Optional | string | The claim to be extracted from the access token containing MongoDB user identifiers. The default value is `sub` (stands for `subject`). | | `useAuthorizationClaim` | Optional | boolean | Determines if the `authorizationClaim` is required. The default value is `true`. If the `useAuthorizationClaim` field is set to `true`, the server requires an `authorizationClaim` for the IdP's config. This is the default behavior. If the `useAuthorizationClaim` field is set to `false`, the `authorizationClaim` field is optional (and ignored if provided). Instead, the server does the following: Searches the token for a claim whose name is listed in the `principalNameClaim` field. This is typically named `sub`. For example:`sub: "spencer.jackson@example.com"`; Constructs the internal username by concatenating the `authNamePrefix`, a forward slash (`/`), and the contents of the claim identified by `principalNameClaim` within the access token. For example, with a `authNamePrefix` field value of "mdbinc", the internal username is:`mdbinc/spencer.jackson@example.com`; Looks for the user with this username and authorizes the client with the roles:`{ user: "mdbinc/spencer.jackson@example.com", db: "$external" }` **New in version 7.2** (*Also available in 7.0.5*) | | `authorizationClaim` | Conditional | string | Required, unless `useAuthorizationClaim` is set to `false`. Claim extracted from access token that contains MongoDB role names. | | `logClaims` | Optional | array[ string ] | List of access token claims to include in log and audit messages upon authentication completion. | | `JWKSPollSecs` | Optional | integer | Frequency, in seconds, to request an updated JSON Web Key Set (JWKS) from the IdP. A setting of 0 disables polling. When more than one IdP is defined, this must be the same value for each configuration that shares an `issuer`. | | `supportsHumanFlows` | Optional | bool | Whether the OIDC provider supports human or machine workflows. This affects the `clientId` and `matchPattern` fields. You may find it useful to set this field to `false` with machine workload IdPs to allow them to omit the `clientId` when it's unneeded. Default: `true`. **New in version 7.2** | This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Available on Linux only* With the use of native TLS/SSL libraries, the parameter [`opensslCipherConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherConfig) is supported for Linux/BSD and no longer supported in Windows and macOS. Specify the cipher string for OpenSSL when using TLS/SSL encryption. For a list of cipher strings, see [https://www.openssl.org/docs/man1.1.1/man1/ciphers.html](https://www.openssl.org/docs/man1.1.1/man1/ciphers.html). Multiple cipher strings can be provided as a colon-separated list. **Note:** This parameter is only for use with TLS 1.2 or earlier. To specify cipher suites for use with TLS 1.3, use the [`opensslCipherSuiteConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherSuiteConfig) parameter. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The use of `TLS` options is preferred over `SSL` options. The TLS options have the same functionality as the `SSL` options. The following example configures a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) with a [`opensslCipherConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherConfig) cipher string of `'HIGH:!EXPORT:!aNULL@STRENGTH'`: ```bash mongod --setParameter opensslCipherConfig='HIGH:!EXPORT:!aNULL@STRENGTH' --tlsMode requireTLS --tlsCertificateKeyFile Certs/server.pem ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 5.0** *Available on Linux only* Specify the list of supported cipher suites OpenSSL should permit when using TLS 1.3 encryption. For a list of cipher suites for use with TLS 1.3, see [https://www.openssl.org/docs/man1.1.1/man3/SSL\_CTX\_set\_cipher\_list.html](https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_cipher_list.html). Multiple cipher suites can be provided as a colon-separated list. **Note:** This parameter is only for use with TLS 1.3. To specify cipher strings for use with TLS 1.2 or earlier, use the [`opensslCipherConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherConfig) parameter. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following configures a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) with a [`opensslCipherSuiteConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherSuiteConfig) cipher suite of `'TLS_AES_256_GCM_SHA384'` for use with TLS 1.3: ```bash mongod --setParameter opensslCipherSuiteConfig='TLS_AES_256_GCM_SHA384' --tlsMode requireTLS --tlsCertificateKeyFile Certs/server.pem ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Available on Linux only* Specify the path to the PEM file that contains the OpenSSL Diffie-Hellman parameters when using TLS 1.2 or previous. Specifying the OpenSSL Diffie-Hellman parameters enables support for [Ephemeral Diffie-Hellman (DHE)](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md#std-label-dhe) cipher suites during TLS/SSL encryption. This parameter is not supported for use with TLS 1.3. Ephemeral Diffie-Hellman (DHE) cipher suites (and Ephemeral Elliptic Curve Diffie-Hellman (ECDHE) cipher suites) provide [Forward Secrecy](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md#std-label-tls-forward-secrecy). [Forward Secrecy](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md#std-label-tls-forward-secrecy) cipher suites create an ephemeral session key that is protected by the server's private key but never transmitted. This ensures that even if a server's private key is compromised, you cannot decrypt past sessions with the compromised key. **Note:** If [`opensslDiffieHellmanParameters`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslDiffieHellmanParameters) is unset but [ECDHE](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md#std-label-ecdhe) is enabled, MongoDB enables DHE using the `ffdhe3072` Diffie-Hellman parameter, as defined in [RFC-7919#appendix-A.2](https://tools.ietf.org/html/7919#appendix-A.2). The `ffdhe3072` is a strong parameter (specifically, size is greater than 1024). Strong parameters are not supported with Java 6 and 7 unless extended support has been purchased from Oracle. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. If for performance reasons, you need to disable support for DHE cipher suites, use the [`opensslCipherConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.opensslCipherConfig) parameter: ```bash mongod --setParameter opensslCipherConfig='HIGH:!EXPORT:!aNULL:!DHE:!kDHE@STRENGTH' ... ``` *Available on Linux only* *Type:* boolean *Default:* false When set to `true`, instructs the server to check the connectivity of accepted connections before processing them and to immediately discard connections that the client terminates. Consider enabling this parameter on smaller instance types. You can use it when you want to trade a small amount of latency on new connection establishment for reduced server work when processing new connections that have already been closed on the client side. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **Note: Available only in MongoDB Enterprise (except MongoDB Enterprise for Windows).** Specify the path to the Unix Domain Socket of the `saslauthd` instance to use for proxy authentication. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) [`saslHostName`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.saslHostName) overrides MongoDB's default hostname detection for the purpose of configuring SASL and Kerberos authentication. [`saslHostName`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.saslHostName) does not affect the hostname of the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance for any purpose beyond the configuration of SASL and Kerberos. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **Note:** [`saslHostName`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.saslHostName) supports Kerberos authentication and is only included in MongoDB Enterprise. For more information, see the following: - Linux: [Configure MongoDB with Kerberos Authentication on Linux](https://www.mongodb.com/docs/manual/tutorial/control-access-to-mongodb-with-kerberos-authentication.md) - Windows: [Configure MongoDB with Kerberos Authentication on Windows](https://www.mongodb.com/docs/manual/tutorial/control-access-to-mongodb-windows-with-kerberos-authentication.md) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Allows users to override the default [Kerberos](https://www.mongodb.com/docs/manual/tutorial/control-access-to-mongodb-with-kerberos-authentication.md) service name component of the [Kerberos](https://www.mongodb.com/docs/manual/tutorial/control-access-to-mongodb-with-kerberos-authentication.md) principal name, on a per-instance basis. If unspecified, the default value is `mongodb`. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`saslServiceName`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.saslServiceName) is only available in MongoDB Enterprise. **Important:** Ensure that your driver supports alternate service names. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `10000` Changes the number of hashing iterations used for all new `SCRAM-SHA-1` passwords. More iterations increase the amount of time required for clients to authenticate to MongoDB, but makes passwords less susceptible to brute-force attempts. The default value is ideal for most common use cases and requirements. If you modify this value, it does not change the iteration count for existing passwords. The [`scramIterationCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.scramIterationCount) value must be `5000` or greater. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`scramIterationCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.scramIterationCount) to `12000`. ```bash mongod --setParameter scramIterationCount=12000 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, scramIterationCount: 12000 } ) ``` **See also:** - [`db.changeUserPassword()`](https://www.mongodb.com/docs/manual/reference/method/db.changeUserPassword.md#mongodb-method-db.changeUserPassword) - [`db.createUser()`](https://www.mongodb.com/docs/manual/reference/method/db.createUser.md#mongodb-method-db.createUser) - [`db.updateUser()`](https://www.mongodb.com/docs/manual/reference/method/db.updateUser.md#mongodb-method-db.updateUser) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `15000` Changes the number of hashing iterations used for all new `SCRAM-SHA-256` passwords. More iterations increase the amount of time required for clients to authenticate to MongoDB, but makes passwords less susceptible to brute-force attempts. The default value is ideal for most common use cases and requirements. If you modify this value, it does not change iteration count for existing passwords. The [`scramSHA256IterationCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.scramSHA256IterationCount) value must be `5000` or greater. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`scramSHA256IterationCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.scramSHA256IterationCount) to `20000`. ```bash mongod --setParameter scramSHA256IterationCount=20000 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, scramSHA256IterationCount: 20000 } ) ``` **See also:** - [`db.changeUserPassword()`](https://www.mongodb.com/docs/manual/reference/method/db.changeUserPassword.md#mongodb-method-db.changeUserPassword) - [`db.createUser()`](https://www.mongodb.com/docs/manual/reference/method/db.createUser.md#mongodb-method-db.createUser) - [`db.updateUser()`](https://www.mongodb.com/docs/manual/reference/method/db.updateUser.md#mongodb-method-db.updateUser) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Set the `net.ssl.mode` to either `preferSSL` or `requireSSL`. Useful during [rolling upgrade to TLS/SSL](https://www.mongodb.com/docs/manual/tutorial/upgrade-cluster-to-ssl.md) to minimize downtime. For more information about TLS/SSL and MongoDB, see [Configure MongoDB Instances for TLS/SSL Encryption](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md) and [TLS/SSL Configuration for Clients](https://www.mongodb.com/docs/manual/tutorial/configure-ssl-clients.md) . This parameter is only available at runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. ```bash db.adminCommand( { setParameter: 1, sslMode: "preferSSL" } ) ``` **See also:** [`tlsMode`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsMode) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 7.0** Overrides the [`clusterAuthX509`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.clusterAuthX509) configuration options. ```yaml setParameter: tlsClusterAuthX509Override: "{ attributes: 'O=MongoDB, OU=MongoDB Server' }" ``` The parameter supports `attributes` and `extensionValue` overrides. When the server authenticates connections from members, it analyzes the X.509 certificate to determine whether it belongs to a cluster member. If the server uses the [`attributes`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.clusterAuthX509.attributes) setting or the `attributes` field on the [`tlsClusterAuthX509Override`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsClusterAuthX509Override) parameter, it checks the Distinguished Name (DN) values of the certificate. If the [`extensionValue`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.clusterAuthX509.extensionValue) setting or the `extensionValue` field of the [`tlsClusterAuthX509Override`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsClusterAuthX509Override) parameter is set, it checks the extension values of the certificate. If it finds a match, it authorizes the connection as a peer. Use this parameter to rotate certificates when the new certificates have different attributes or extension values. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Set to either: - `preferTLS` - `requireTLS` Use the [`tlsMode`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsMode) parameter during [rolling upgrade to TLS/SSL](https://www.mongodb.com/docs/manual/tutorial/upgrade-cluster-to-ssl.md) to minimize downtime. This parameter is only available at runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. ```bash db.adminCommand( { setParameter: 1, tlsMode: "preferTLS" } ) ``` For more information about TLS/SSL and MongoDB, see [Configure MongoDB Instances for TLS/SSL Encryption](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md) and [TLS/SSL Configuration for Clients](https://www.mongodb.com/docs/manual/tutorial/configure-ssl-clients.md) . **See also:** [`sslMode`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.sslMode) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Available for Linux. The maximum number of seconds the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) / [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance should wait to receive the OCSP status response for its certificates. Specify an integer greater than or equal to (`>=`) 1. If unset, [`tlsOCSPStaplingTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPStaplingTimeoutSecs) uses the [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) value. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`tlsOCSPStaplingTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPStaplingTimeoutSecs) to 20 seconds: ```bash mongod --setParameter tlsOCSPStaplingTimeoutSecs=20 ... ``` **See also:** - [`ocspEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspEnabled) - [`ocspStaplingRefreshPeriodSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspStaplingRefreshPeriodSecs) - [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Available for Linux and Windows. *Default*: 5 The maximum number of seconds that the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) / [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) should wait for the OCSP response when verifying server certificates. Specify an integer greater than or equal to (`>=`) 1. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`tlsOCSPVerifyTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs) to 20 seconds: ```bash mongod --setParameter tlsOCSPVerifyTimeoutSecs=20 ... ``` **See also:** - [`ocspEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspEnabled) - [`ocspStaplingRefreshPeriodSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ocspStaplingRefreshPeriodSecs) - [`tlsOCSPStaplingTimeoutSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsOCSPStaplingTimeoutSecs) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false Specifies whether MongoDB loads TLS certificates that are already available to the operating system's certificate authority. **Important:** When starting a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance with [TLS/SSL enabled](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md#std-label-configure-mongod-mongos-for-tls-ssl), you must specify a value for the [`--tlsCAFile`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsCAFile) flag, the [`net.tls.CAFile`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.CAFile) configuration option, or the [`tlsUseSystemCA`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsUseSystemCA) parameter. `--tlsCAFile`, `tls.CAFile`, and `tlsUseSystemCA` are all mutually exclusive. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set `tlsUseSystemCA` to `true`: ```bash mongod --setParameter tlsUseSystemCA=true ``` For more information about TLS/SSL and MongoDB, see [Configure MongoDB Instances for TLS/SSL Encryption](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md) and [TLS/SSL Configuration for Clients](https://www.mongodb.com/docs/manual/tutorial/configure-ssl-clients.md) . [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: false A TLS certificate is set for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) either by the [`--tlsClusterFile`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsClusterFile) option or by the [`--tlsCertificateKeyFile`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsCertificateKeyFile) option when [`--tlsClusterFile`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsClusterFile) is not set. If the TLS certificate is set, by default, the instance sends the certificate when initiating intra-cluster communications with other [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instances in the deployment. Set `tlsWithholdClientCertificate` to `1` or `true` to direct the instance to withhold sending its TLS certificate during these communications. Use this option with [`--tlsAllowConnectionsWithoutCertificates`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--tlsAllowConnectionsWithoutCertificates) (to allow inbound connections without certificates) on all members of the deployment. `tlsWithholdClientCertificate` is mutually exclusive with [`--clusterAuthMode x509`.](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--clusterAuthMode) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) An alternative Distinguished Name (DN) that the instance can also use to identify members of the deployment. For a MongoDB deployment that uses X.509 certificates for [`clusterAuthMode`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.clusterAuthMode), deployment members identify each other using X.509 certificates ( [`net.tls.clusterFile`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.clusterFile), if specified, and [`net.tls.certificateKeyFile`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.certificateKeyFile)) during intra-cluster communications. For members of the same deployment, the `DN` from their certificates must have the same Organization attributes (`O`'s), the Organizational Unit attributes (`OU`'s), and the Domain Components (`DC`'s). If [`tlsX509ClusterAuthDNOverride`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsX509ClusterAuthDNOverride) is set for a member, the member can also use the override value when comparing the `DN` components (`O`'s, `OU`'s, and `DC`'s) of the presented certificates. That is the member checks the presented certificates against its [`net.tls.clusterFile`/](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.clusterFile)[`net.tls.certificateKeyFile`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-net.tls.certificateKeyFile). If the DN does not match, the member checks the presented certificate against the [`tlsX509ClusterAuthDNOverride`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsX509ClusterAuthDNOverride) value. **Note:** If set, you must set this parameter on all members of the deployment. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. You can use this parameter for a rolling update of certificates to new certificates that contain a new `DN` value. See [Rotate Certificates on Clusters without clusterAuthX509.](https://www.mongodb.com/docs/manual/tutorial/rotate-x509-membership-certificates.md) For more information about membership certificate requirements, see [Member Certificate Requirements](https://www.mongodb.com/docs/manual/core/security-x.509.md#std-label-x509-member-certificate-requirements) for details. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default* : 30 [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) / [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) logs a warning on connection if the presented X.509 certificate expires within `30` days of the `mongod/mongos` system clock. Use the [`tlsX509ExpirationWarningThresholdDays`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tlsX509ExpirationWarningThresholdDays) parameter to control the certificate expiration warning threshold: - Increase the parameter value to trigger warnings farther ahead of the certificate expiration date. - Decrease the parameter value to trigger warnings closer to the certificate expiration date. - Set the parameter to `0` to disable the warning. This parameter has a minimum value of `0`. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For more information on X.509 certificate validity, see [RFC 5280 4.1.2.5.](https://tools.ietf.org/html/rfc5280#section-4.1.2.5) [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Default*: 30 On a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance, specifies the interval (in seconds) at which the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance checks to determine whether the in-memory cache of [user objects](https://www.mongodb.com/docs/manual/reference/system-users-collection.md) has stale data, and if so, clears the cache. If there are no changes to user objects, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) will not clear the cache. This parameter has a minimum value of `1` second and a maximum value of `86400` seconds (24 hours). This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ### General Parameters [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: True Pipeline stages that require more than 100 megabytes of memory to execute write temporary files to disk by default. These temporary files last for the duration of the pipeline execution and can influence storage space on your instance. Individual `find` and `aggregate` commands can override the [`allowDiskUseByDefault`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.allowDiskUseByDefault) parameter by either: - Using `{ allowDiskUse: true }` to allow writing temporary files out to disk when `allowDiskUseByDefault` is set to `false` - Using `{ allowDiskUse: false }` to prohibit writing temporary files out to disk when `allowDiskUseByDefault` is set to `true` This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter allowDiskUseByDefault=false ``` [`allowDiskUseByDefault`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.allowDiskUseByDefault) only works on [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) not [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos). [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) never writes temporary files to disk. Use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) to change the value of the parameter while the server is running: ```javascript db.adminCommand( { setParameter: 1, allowDiskUseByDefault: false } ) ``` **New in version 8.3** *(also available starting in 8.2.4, 8.0.18, and 7.0.29)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Int *Default*: 20 Specifies the maximum percentage of total memory to allocate to pre-auth buffers for connections. Setting the parameter to `100` disables this limitation. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following operation sets `capMemoryConsumptionForPreAuthBuffers` to `30`: ```bash mongod --setParameter capMemoryConsumptionForPreAuthBuffers=30 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 200 Sets the maximum size of the legacy connection pools for outgoing connections to other [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances in the global connection pool. The size of a pool does not prevent the creation of additional connections, but *does* prevent a connection pool from retaining connections in excess of the value of [`connPoolMaxConnsPerHost`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.connPoolMaxConnsPerHost) **Note:** The parameter is separate from the connections in TaskExecutor pools. See [`ShardingTaskExecutorPoolMaxSize`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) **Only** adjust this setting if your driver does *not* pool connections and you're using authentication in the context of a sharded cluster. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter connPoolMaxConnsPerHost=250 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Sets the maximum number of in-use connections at any given time for for outgoing connections to other [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances in the legacy global connection pool. By default, the parameter is unset. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter connPoolMaxInUseConnsPerHost=100 ``` **See also:** [`connPoolMaxConnsPerHost`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.connPoolMaxConnsPerHost) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 600000 (10 minutes) Sets the expiration threshold in milliseconds for idle cursors before MongoDB removes them; specifically, MongoDB removes cursors that have been idle for the specified [`cursorTimeoutMillis`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.cursorTimeoutMillis) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`cursorTimeoutMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.cursorTimeoutMillis) to `300000` milliseconds (5 minutes). ```bash mongod --setParameter cursorTimeoutMillis=300000 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, cursorTimeoutMillis: 300000 } ) ``` Setting [`cursorTimeoutMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.cursorTimeoutMillis) to less than or equal to `0` results in all cursors being immediately eligible for timeout. Generally, the timeout value should be greater than the average amount of time for a query to return results. Use tools like the [`cursor.explain()`](https://www.mongodb.com/docs/manual/reference/method/cursor.explain.md#mongodb-method-cursor.explain) cursor modifier to analyze the average query time and select an appropriate timeout period. **Warning:** MongoDB cleans up [orphaned cursors](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-orphaned-cursor) after the `cursorTimeoutMillis` threshold only if they are not tied to sessions. MongoDB cleans up cursors linked to sessions with the [`localLogicalSessionTimeoutMinutes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.localLogicalSessionTimeoutMinutes) lifecycle, regardless of the `cursorTimeoutMillis` value. To handle long idle periods, use [`Mongo.startSession()`](https://www.mongodb.com/docs/manual/reference/method/Mongo.startSession.md#mongodb-method-Mongo.startSession) and refresh the session using the [`refreshSessions`](https://www.mongodb.com/docs/manual/reference/command/refreshSessions.md#mongodb-dbcommand-dbcmd.refreshSessions) command. For details, see [Refresh a Cursor with `refreshSessions`.](https://www.mongodb.com/docs/manual/reference/method/cursor.noCursorTimeout.md#std-label-refresh-session-cursor-example) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Default: 100 Base delay in milliseconds for the default retry strategy used in internal server-side connections, such as [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) and [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-program-mongod). The server uses this value as the initial delay for exponential backoff between retries on operations that fail due to overload. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Default: 10,000 Maximum delay in milliseconds for the default retry strategy used by internal server-side client connections, such as [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) and [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-program-mongod). The server uses this value as the maximum wait time between retries of operations that fail due to overload. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Default: 3 Maximum number of times the server retries an operation for internal server-side client connections, such as [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) and [`mongod`.](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-program-mongod) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.3** **New in version 5.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Default: 15 seconds Allows a server that receives a request to step up or step down, to terminate if it is unable to comply (for example due to faulty server disks) within the timeout. This enables a cluster to successfully elect a new primary node and thus continue to be available. `fassertOnLockTimeoutForStepUpDown` defaults to 15 seconds. To disable nodes from fasserting, set `fassertOnLockTimeoutForStepUpDown=0`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example disables nodes from fasserting: ```bash mongod --setParameter fassertOnLockTimeoutForStepUpDown=0 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Sets the time limit that connection in the legacy global connection pool can remain idle before being closed. By default, the parameter is unset. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongos --setParameter globalConnPoolIdleTimeoutMinutes=10 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Adds more verbose tracing for curl on Linux and macOS. Has no affect on Windows. By default, the parameter is unset. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongos --setParameter httpVerboseLogging=true ``` **New in version 7.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 500 MB Sets the minimum available disk space in megabytes required for index builds. Must be greater than or equal to 0 MB, and less than or equal to 8 TB. 0 disables the minimum disk space requirement. A new index build cannot be started and a current index build is cancelled if the available disk space is below `indexBuildMinAvailableDiskSpaceMB`. **Warning:** If you increase `indexBuildMinAvailableDiskSpaceMB`, ensure your server has enough available disk space. Also, if you set `indexBuildMinAvailableDiskSpaceMB` too high, you might needlessly prevent index builds when there is enough available disk space and `indexBuildMinAvailableDiskSpaceMB` could be set lower. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets `indexBuildMinAvailableDiskSpaceMB` to 650 MB: ```javascript db.adminCommand( { setParameter: 1, indexBuildMinAvailableDiskSpaceMB: 650 } ) ``` You can also set `indexBuildMinAvailableDiskSpaceMB` at startup. For example: ```bash mongod --setParameter indexBuildMinAvailableDiskSpaceMB=650 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 5.3** *Default*: 100000 Limits the maximum number of keys generated for a document to prevent out of memory errors. It is possible to raise the limit, but if an operation requires more keys than the [`indexMaxNumGeneratedKeysPerDocument`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.indexMaxNumGeneratedKeysPerDocument) parameter specifies, the operation will fail. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `1000000` Controls the maximum number of operations admitted concurrently to the ingress queue. The default value of `1000000` represents the numerical equivalent of unbounded, which admits all incoming operations up to the default maximum connections that MongoDB allows. Increasing this value while there are operations waiting on the queue unblocks as many operations as the new pool size permits. Decreasing this value does not block any currently executing operations, but incoming controllable operations are blocked until there are tickets available. ```bash mongod --setParameter ingressAdmissionControllerTicketPoolSize=100000 ``` **Warning:** Avoid modifying [`ingressAdmissionControllerTicketPoolSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ingressAdmissionControllerTicketPoolSize) unless directed by MongoDB engineers. This setting has major implications across both WiredTiger and MongoDB. **New in version 8.2** *(also available in 8.1.1 and 8.0.12)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: `false` Determines whether rate limiting for new connection establishment is enabled. When enabled, MongoDB applies rate limiting to control the number of new connections that can be established per second. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.2** *(also available in 8.1.1 and 8.0.12)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: int32 *Default*: disabled *Minimum*: 1 Specifies the maximum number of new connections that can be established per second when rate limiting is enabled. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.2** *(also available in 8.1.1 and 8.0.12)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: double *Default*: disabled *Minimum*: 1 Describes how many seconds worth of connection establishments that the server can admit before rate limiting begins. This allows the server to handle temporary bursts of connection requests that exceed the rate limit specified by [`ingressConnectionEstablishmentRatePerSec`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ingressConnectionEstablishmentRatePerSec) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.2** *(also available in 8.1.1 and 8.0.12)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: int32 *Default*: `0` (disabled) Specifies the maximum number of connection attempts in the connection establishment queue. After the queue reaches this number of connection attempts, the server rejects new connection attempts. The default value of `0` means that the server rejects all connections that will queue for establishment. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.2** *(also available in 8.1.1 and 8.0.12)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: string array *Default*: `[]` Provides a list of IP addresses and CIDR ranges that the server must exempt from the connection establishment rate limits. This allows specific trusted clients to bypass rate limiting restrictions. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Document containing an array of strings given by the key `appNames` *Default*: `{ appnames: [] }` The `ingressRequestRateLimiterApplicationExemptions` parameter lets you specify applications to exempt from ingress request rate limiting. `ingressRequestRateLimiterApplicationExemptions` accepts a document containing an array of application names to exempt from ingress request rate limiting as input. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following command exempts the connections with the [application name](https://github.com/mongodb/specifications/blob/master/source/mongodb-handshake/handshake.md#clientapplicationname) "MongoDB Internal Client" at startup: ```javascript db.adminCommand( { setParameter: 1, ingressRequestRateLimiterApplicationExemptions: { appNames: ["MongoDB Internal Client"], } } ) ``` The following command exempts connections with the application name "MongoDB Internal Client" during run time: ```javascript mongod \ --setParameter "ingressRequestRateLimiterApplicationExemptions={\"appNames\":[\"MongoDB Internal Client\"]}" ``` **New in version 8.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: `false` This parameter controls whether overload-induced retries against other servers in the cluster avoid servers that recently returned an error labeled `SystemOverloadedError`. It affects operations that perform remote targeting, for example when `mongos` retries requests against shard members or when `mongod` performs remote reads during aggregation. When you set this parameter to `true`, retry logic for remote targeting prefers non-overloaded members for operations that fail with `SystemOverloadedError`. For example, when `mongos` retries reads: - With the `primaryPreferred` read preference, `mongos` can route a retried read to a secondary if the primary indicates overload, even if the primary remains reachable. - With the `secondaryPreferred` read preference, `mongos` can route a retried read to the primary if secondaries indicate overload. When you set this parameter to `false`, retries do not avoid members that signal overload. If a member continues to return `SystemOverloadedError`, retries may continue targeting that member. This parameter affects only operations retried after `SystemOverloadedError` errors that can occur when you enable ingress request rate limiting or other overload mechanisms on shard nodes. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default (absolute)*: 200*Minimum (absolute)*: 50*Maximum (percent)*: 0.8 Limits the amount of memory that simultaneous [index builds](https://www.mongodb.com/docs/manual/core/index-creation.md#std-label-index-build-process) on one collection may consume for their duration. The specified amount of memory is shared between all indexes built using a single [`createIndexes`](https://www.mongodb.com/docs/manual/reference/command/createIndexes.md#mongodb-dbcommand-dbcmd.createIndexes) command or its shell helper [`db.collection.createIndexes()`](https://www.mongodb.com/docs/manual/reference/method/db.collection.createIndexes.md#mongodb-method-db.collection.createIndexes). Increasing the limit may avoid negative performance impacts in some cases, such as when building numerous indexes simultaneously with a single [`createIndexes`](https://www.mongodb.com/docs/manual/reference/command/createIndexes.md#mongodb-dbcommand-dbcmd.createIndexes) command and/or when working with index key data set sizes that exceed 500GB. The memory consumed by an index build is separate from the WiredTiger cache memory (see [`cacheSizeGB`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.wiredTiger.engineConfig.cacheSizeGB)). - Set this value to 0-0.8 to limit builds to a percentage of memory. - Set this value to 1.0 or greater to limit builds to an absolute number of megabytes. If this setting allocates less than 50 MB, `mongod` uses a minimum of 50 MB. If the percentage setting is greater than 0.8, `mongod` uses a maximum of 80% of available memory. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 3 Sets the maximum number of index build requests that MongoDB can perform concurrently. `maxNumActiveUserIndexBuilds` is a global limit that applies for all collections. The following table shows the default values for `maxNumActiveUserIndexBuilds` based on Atlas tiers: | **Atlas Tiers** | **maxNumActiveUserIndexBuilds Default** | | --- | --- | | Small M tiers (`M10`, `M20`, `M30`, `M40`) | `1` | | Medium M tiers (`M50`, `M60`) | `2` | | Large M tiers (`M80` and higher, including NMVe variants) | `3` | **Note:** These defaults also apply to the corresponding low-CPU `R` tiers. The [`createIndexes`](https://www.mongodb.com/docs/manual/reference/command/createIndexes.md#mongodb-dbcommand-dbcmd.createIndexes) command builds indexes. Even if the `createIndexes` command builds multiple indexes at once, the command execution only adds `1` to `maxNumActiveUserIndexBuilds`. Increasing the value of `maxNumActiveUserIndexBuilds` allows additional concurrent index builds at the cost of increased pressure on the WiredTiger cache. System indexes are not limited to `maxNumActiveUserIndexBuilds`, however a system index build counts against the limit for user index builds. After the server reaches `maxNumActiveUserIndexBuilds`, it blocks additional user index builds until the number of concurrent index builds drops below the `maxNumActiveUserIndexBuilds` limit. If an index build is blocked, the server logs this message: ```sh Too many index builds running simultaneously, waiting until the number of active index builds is below the threshold. ``` This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following command sets a limit of 4 concurrent index builds: ```javascript db.adminCommand( { setParameter: 1, maxNumActiveUserIndexBuilds: 4 } ) ``` See also: - [`maxIndexBuildMemoryUsageMegabytes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxIndexBuildMemoryUsageMegabytes) - [Index Builds on Populated Collections](https://www.mongodb.com/docs/manual/core/index-creation.md#std-label-index-creation-background) **New in version 8.3** *(also available starting in 8.2.4, 8.0.18, and 7.0.29)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Int *Default*: 5 Specifies the rate, in seconds, at which the server logs message size errors at the Info level. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following operation sets `messageSizeErrorRateSec` to `6`: ```bash mongod --setParameter messageSizeErrorRateSec=6 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Prevents running some collection scans when an index could be used, whether present or not. If `true`, MongoDB will not execute queries that require a collection scan and will return an error. Exclusions include queries without filters and queries against capped collections, such as the oplog. Consider the following example which sets [`notablescan`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.notablescan) to `true` or true: ```javascript db.adminCommand( { setParameter: 1, notablescan: true } ) ``` Set [`notablescan`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.notablescan) to `true` to test application queries and identify queries that scan an entire collection and cannot use an index. To detect unindexed queries without `notablescan`, consider reading the [Analyze Query Performance](https://www.mongodb.com/docs/manual/tutorial/evaluate-operation-performance.md) section and using the [`logLevel`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.logLevel) parameter, [`mongostat`](https://www.mongodb.com/docs/database-tools/mongostat.md#mongodb-binary-bin.mongostat) and [profiling.](https://www.mongodb.com/docs/manual/tutorial/manage-the-database-profiler.md#std-label-database-profiling) Don't run production [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances with [`notablescan`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.notablescan) because preventing collection scans can potentially affect queries in all databases, including administrative queries. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **Note:** `notablescan` does not allow unbounded queries that use a clustered index because the queries require a full collection scan. For more information, see [Collection Scans.](https://www.mongodb.com/docs/manual/reference/explain-results.md#std-label-explain-output-collection-scan) **New in version 8.3** *(also available starting in 8.2.4, 8.0.18, and 7.0.29)* [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Int *Default*: 16384 (16 KiB) The maximum size of a message in bytes that you can send before the session authenticates. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the maximum size of the message to 1700 bytes: ```bash mongod --setParameter preAuthMaximumMessageSizeBytes=1700 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, preAuthMaximumMessageSizeBytes: 1700 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: false A boolean flag that determines whether the [`db.serverStatus()`](https://www.mongodb.com/docs/manual/reference/method/db.serverStatus.md#mongodb-method-db.serverStatus) method and [`serverStatus`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-dbcommand-dbcmd.serverStatus) command return [`opWriteConcernCounters`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.opWriteConcernCounters) information. ```bash mongod --setParameter reportOpWriteConcernCountersInServerStatus=true ``` Enabling [`reportOpWriteConcernCountersInServerStatus`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.reportOpWriteConcernCountersInServerStatus) can have a negative performance impact; specifically, when running *without* TLS. **New in version 6.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 100 Sets the time limit in milliseconds to log the establishment of slow server connections. If a connection takes longer to establish than the [`slowConnectionThresholdMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.slowConnectionThresholdMillis) parameter, an event is added to the [log](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-messages-ref) with the message `msg` field set to `"Slow connection establishment"`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`slowConnectionThresholdMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.slowConnectionThresholdMillis) to `250` milliseconds. ```bash mongod --setParameter slowConnectionThresholdMillis=250 ``` Or, if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, slowConnectionThresholdMillis: 250 } ) ``` **Warning:** `tcmallocAggressiveMemoryDecommit` is deprecated in 8.0. MongoDB 8.0 uses an updated version of `tcmalloc` that improves memory fragmentation and management. See [tcmalloc upgrade](https://www.mongodb.com/docs/manual/release-notes/8.0.md#std-label-8.0-tcmalloc-upgrade) for more information. To release memory back to the operating system, consider using [`tcmallocEnableBackgroundThread`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tcmallocEnableBackgroundThread) instead. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.0** *Type*: boolean Default: true If set to `true`, `tcmallocEnableBackgroundThread` creates a background thread that periodically releases memory back to the operating system. The value of [`tcmallocReleaseRate`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tcmallocReleaseRate) determines the rate, in bytes per second, at which the background thread releases memory. **Note:** If `tcmallocEnableBackgroundThread` is `true` and `tcmallocReleaseRate` is `0`, MongoDB still releases memory. For improved memory usage, we recommend using the default value of `true`. To learn more about improvements to performance and memory management, see [Upgraded TCMalloc.](https://www.mongodb.com/docs/manual/release-notes/8.0.md#std-label-8.0-tcmalloc-upgrade) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following operation sets `tcmallocEnableBackgroundThread` to `false`: ```bash mongod --setParameter "tcmallocEnableBackgroundThread=false" ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **Changed in version 8.0** Default: 0 Specifies the [TCMalloc release rate](https://github.com/google/tcmalloc/blob/master/docs/tuning.md) in bytes per second. Release rate refers to the rate at which MongoDB releases unused memory to the system. If `tcmallocReleaseRate` is set to `0` MongoDB doesn't release memory back to the system. Increase this value to return memory faster; decrease it to return memory slower. If `tcmallocReleaseRate` is a small non-zero value, the actual memory release rate can exceed the configured value. TCMalloc releases memory at page-span granularity, and a page span can consist of multiple TCMalloc pages. **Note:** If `tcmallocEnableBackgroundThread` is `true` and `tcmallocReleaseRate` is `0`, MongoDB still releases memory. Starting in MongoDB 8.0, the default value of `tcmallocReleaseRate` is reduced to `0` due to a [tcmalloc upgrade](https://www.mongodb.com/docs/manual/release-notes/8.0.md#std-label-8.0-tcmalloc-upgrade) that prioritizes CPU performance over memory release. In earlier versions, MongoDB used an older version of `tcmalloc` that: - Set the default `tcmallocReleaseRate` to `1`. - Accepted values for `tcmallocReleaseRate` between `0` and `10`, inclusive. **Important:** If you run MongoDB on a platform that uses `tcmalloc-gperf` such as Windows, PPC, or s390x, `tcmallocReleaseRate` has the same behavior as earlier MongoDB versions. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. To modify the release rate during run time, you can use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. For example: ```javascript db.adminCommand( { setParameter: 1, tcmallocReleaseRate: 2097152 } ) ``` You can also set [`tcmallocReleaseRate`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.tcmallocReleaseRate) at startup time; for example: ```bash mongod --setParameter "tcmallocReleaseRate=2097152" ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `true` *Linux Operating System Only* Enables support for outbound TCP Fast Open (TFO) connections from the `mongod/mongos` to a client. TFO requires both the client and the `mongod/mongos` host machine support and enable TFO. Linux operating systems running Linux Kernel 4.11 or later can support outbound TFO. Set the value of `/proc/sys/net/ipv4/tcp_fastopen` to enable outbound TFO connections: - `1` to enable only outbound TFO connections. - `3` to enable inbound and outbound TFO connections. This parameter has no effect if the host operating system does not support *or* is not configured to support TFO connections. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** [RFC7413.](https://tools.ietf.org/html/rfc7413) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `1024` As part of establishing a TCP Fast Open (TFO) connection, the client submits a valid TFO cookie to the `mongod/mongos` *before* completion of the standard TCP 3-way handshake. The `mongod/mongos` keeps a queue of all such pending TFO connections. The `tcpFastOpenQueueSize` parameter sets the size of the queue of pending TFO connections. While the queue is full, the `mongod/mongos` falls back to the normal three-way handshake for incoming client requests and ignores the presence of TFO cookies. Once the queue size falls back below the limit, the `mongod/mongos` begins accepting new TFO cookies. - Increasing the default queue size may improve the effect of TFO on network performance. However, large queue sizes also increase the risk of server resource exhaustion due to excessive incoming TFO requests. - Decreasing the default queue size may reduce the risk of resource server resource exhaustion due to excessive incoming TFO requests. However, small queue sizes may also reduce the effect of TFO on network performance. The minimum queue size is `0`. A queue of `0` effectively disables TFO. This parameter has no effect on host operating systems that do not support or are not configured for TFO connections. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** - [RFC7413 TCP Fast Open Section 5: Security Considerations](https://tools.ietf.org/html/rfc7413#section-5) - [RFC7413 TCP Fast Open Section 6: TFO Applicability](https://tools.ietf.org/html/rfc7413#section-6) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `true` Enables support for accepting inbound TCP Fast Open (TFO) connections to the `mongod/mongos` from a client. TFO requires both the client and `mongod/mongos` host machine support and enable TFO: Windows The following Windows operating systems support TFO: - Microsoft Windows Server 2016 and later. - Microsoft Windows 10 Update 1607 and later. macOS macOS 10.11 (El Capitan) and later support TFO. Linux Linux operating systems running Linux Kernel 3.7 or later can support inbound TFO. Set the value of `/proc/sys/net/ipv4/tcp_fastopen` to enable inbound TFO connections: - Set to `2` to enable only inbound TFO connections. - Set to `3` to enable inbound and outbound TFO connections. This parameter has no effect if the host operating system does not support *or* is not configured to support TFO connections. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** [RFC7413.](https://tools.ietf.org/html/rfc7413) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `true` To support [TTL Indexes](https://www.mongodb.com/docs/manual/core/index-ttl.md#std-label-index-feature-ttl), [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances have a background thread that is responsible for deleting documents from collections with TTL indexes. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. To disable this worker thread for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), set [`ttlMonitorEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ttlMonitorEnabled) to `false`, as in the following operations: ```javascript db.adminCommand( { setParameter: 1, ttlMonitorEnabled: false } ) ``` Alternately, you may disable the thread at startup time by starting the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance with the following option: ```bash mongod --setParameter ttlMonitorEnabled=false ``` **Important:** Do not run production [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances with `ttlMonitorEnabled` disabled, except under guidance from MongoDB support. Preventing TTL document removal can negatively impact MongoDB internal system operations that depend on TTL Indexes. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: -1 (disabled) Determines how frequent the [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog) checks the status of the monitored filesystems: - The [`--dbpath`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--dbpath) directory - The `journal` directory inside the [`--dbpath`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--dbpath) directory - The directory of [`--logpath`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--logpath) file - The directory of [`--auditPath`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--auditPath) file Valid values for [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) are: - `-1` (the default), to disable/pause [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog), or - An integer greater than or equal to 60. **Note:** - If a filesystem on a monitored directory becomes unresponsive, it can take a maximum of nearly *twice* the value of [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) to terminate the [`mongod`.](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) - If any of its monitored directory is a symlink to other volumes, the Storage Node Watchdog does not monitor the symlink target. For example, if the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) uses [`storage.directoryPerDB: true`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.directoryPerDB) (or [`--directoryperdb`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--directoryperdb)) and symlinks a database directory to another volume, the Storage Node Watchdog does not follow the symlink to monitor the target. To enable [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog), [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) must be set during startup. ```bash mongod --setParameter watchdogPeriodSeconds=60 ``` You can only enable the [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog) at startup. However, once enabled, you can pause the [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog) or change the [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) during run time. Once enabled, - To pause the [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog) during run time, set [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) to -1. ```javascript db.adminCommand( { setParameter: 1, watchdogPeriodSeconds: -1 } ) ``` - To resume or change the period during run time, set [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) to a number greater than or equal to 60. ```javascript db.adminCommand( { setParameter: 1, watchdogPeriodSeconds: 120 } ) ``` **Note:** It is an error to set [`watchdogPeriodSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.watchdogPeriodSeconds) at run time if the [Storage Node Watchdog](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-storage-node-watchdog) was not enabled at startup time. ### Logging Parameters **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true Determines whether to enable specific log messages related to cluster connection health metrics. If [`enableDetailedConnectionHealthMetricLogLines`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.enableDetailedConnectionHealthMetricLogLines) is set to `false`, the following log messages are turned off, but MongoDB still collects data on the cluster connection health metrics: | Log Message | Description | | --- | --- | | Accepted TLS connection from peer | Indicates that the server successfully parsed the peer certificate during the TLS handshake with an accepted ingress connection. | | Ingress TLS handshake complete | Indicates that the TLS handshake with an ingress connection is complete. | | Hello completed | Indicates that the initial connection handshake completed on an incoming client connection. MongoDB displays the log message only with the first `hello` command. | | Auth metrics report | Specifies the completion of a step in the authentication conversation. | | Received first command on ingress connection since session start or auth handshake | Indicates that an ingress connection received the first command that is not part of the handshake. | | Slow network response send time | Indicates that the time spent, in milliseconds, to send the response back to the client over an ingress connection takes more time than the duration defined by the `slowMS` server parameter. | | Completed client-side verification of OCSP request | If the peer doesn't include an OCSP (Online Certificate Status Protocol) response to the TLS handshake when an egress TLS connection is established, the server must send an OCSP request to the certificate authority. MongoDB writes this log message when the certificate authority receives the OCSP response. | | Slow connection establishment | Indicates that the time taken to send a response back to the client over an ingress connection takes longer than the threshold specified with the [`slowConnectionThresholdMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.slowConnectionThresholdMillis) parameter. MongoDB also emits this log message when the connection establishment times out. | | Operation timed out while waiting to acquire connection | Indicates that an operation timed out while waiting to acquire an egress connection. | | Acquired connection for remote operation and completed writing to wire | Indicates that the server took one millisecond or longer to write an outgoing request on an egress connection, counting from the instant when the connection establishes. | This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 0 Sets the verbosity levels of various [components](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-message-components) for [log messages](https://www.mongodb.com/docs/manual/reference/log-messages.md). The verbosity level determines the amount of [Informational and Debug](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-severity-levels) messages MongoDB outputs. The verbosity level can range from `0` to `5`: - `0` is the MongoDB's default log verbosity level, to include [Informational](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-severity-levels) messages. - `1` to `5` increases the verbosity level to include Debug messages. For a component, you can also specify `-1` to inherit the parent's verbosity level. To specify the verbosity level, use a document similar to the following: ```none { verbosity: , : { verbosity: }, : { verbosity: , : { verbosity: } }, ... } ``` For the components, you can specify just the `: ` in the document, unless you are setting both the parent verbosity level and that of the child component(s) as well: ```none { verbosity: , : , : { verbosity: , : } ... } ``` The top-level `verbosity` field corresponds to [`systemLog.verbosity`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.verbosity) which sets the default level for all components. The default value of [`systemLog.verbosity`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.verbosity) is `0`. The components correspond to the following settings: - [`accessControl`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.accessControl.verbosity) - [`assert`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.assert.verbosity) - [`command`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.command.verbosity) - [`control`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.control.verbosity) - [`ftdc`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.ftdc.verbosity) - [`geo`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.geo.verbosity) - [`index`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.index.verbosity) - [`network`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.network.verbosity) - [`query`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.query.verbosity) - [`query.rejected`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.query.rejected.verbosity) - [`queryStats`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.queryStats.verbosity) - [`replication`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.replication.verbosity) - [`replication.election`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.replication.election.verbosity) - [`replication.heartbeats`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.replication.heartbeats.verbosity) - [`replication.initialSync`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.replication.initialSync.verbosity) - [`replication.rollback`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.replication.rollback.verbosity) - [`recovery`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.recovery.verbosity) - [`sharding`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.sharding.verbosity) - [`storage`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.verbosity) - [`storage.journal`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.journal.verbosity) - [`transaction`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.transaction.verbosity) - [`write`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.write.verbosity) Unless explicitly set, the component has the verbosity level of its parent. For example, `storage` is the parent of `storage.journal`. That is, if you specify a [`storage`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.verbosity) verbosity level, this level also applies to: - [`storage.journal`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.journal.verbosity) components *unless* you specify the verbosity level for [`storage.journal`.](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.journal.verbosity) - [`storage.recovery`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.recovery.verbosity) components *unless* you specify the verbosity level for [`storage.recovery`.](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.recovery.verbosity) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the [`default verbosity level`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.verbosity) to `1`, the [`query`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.query.verbosity) to `2`, the [`storage`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.verbosity) to `2`, and the [`storage.journal`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.component.storage.journal.verbosity) to `1`. ```javascript db.adminCommand( { setParameter: 1, logComponentVerbosity: { verbosity: 1, query: { verbosity: 2 }, storage: { verbosity: 2, journal: { verbosity: 1 } } } } ) ``` You can also set parameter [`logComponentVerbosity`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.logComponentVerbosity) at startup time, passing the verbosity level document as a string. ```bash mongod --setParameter "logComponentVerbosity={command: 3}" ``` [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) also provides the [`db.setLogLevel()`](https://www.mongodb.com/docs/manual/reference/method/db.setLogLevel.md#mongodb-method-db.setLogLevel) to set the log level for a single component. For various ways to set the log verbosity level, see [Configure Log Verbosity Levels.](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-messages-configure-verbosity) Starting in version 4.2, MongoDB includes the Debug verbosity level (1-5) in the [log messages](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-severity-levels). For example, if the verbosity level is 2, MongoDB logs `D2`. In previous versions, MongoDB log messages only specified `D` for Debug level. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 0 (informational) Specify an integer between `0` and `5` signifying the verbosity of the [logging](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-messages-ref), where `5` is the most verbose. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the [`logLevel`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.logLevel) to `2`: ```javascript db.adminCommand( { setParameter: 1, logLevel: 2 } ) ``` **See also:** - [`logComponentVerbosity`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.logComponentVerbosity) - [`systemLog.verbosity`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.verbosity) Starting in version 4.2, MongoDB includes the Debug verbosity level (1-5) in the [log messages](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-severity-levels). For example, if the verbosity level is 2, MongoDB logs `D2`. In previous versions, MongoDB log messages only specified `D` for Debug level. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: non-negative integer *Default*: 10 Specifies the maximum size, in kilobytes, for an individual attribute field in a log entry; attributes exceeding this limit are truncated. Truncated attribute fields print field content up to the [`maxLogSizeKB`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxLogSizeKB) limit and excise field content past that limit, retaining valid JSON formatting. Log entries that contain truncated attributes append a `truncated` object to the end of the log entry. See [log message truncation](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-message-truncation) for more information. A value of `0` disables truncation entirely. Negative values for this parameter are not valid. **Warning:** Using a large value, or disabling truncation with a value of `0`, may adversely affect system performance and negatively impact database operations. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the maximum log line size to `20` kilobytes: ```bash mongod --setParameter maxLogSizeKB=20 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Sets quiet logging mode. If `1`, [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) will go into a quiet logging mode which will not log the following events/activities: - connection events; - the [`drop`](https://www.mongodb.com/docs/manual/reference/command/drop.md#mongodb-dbcommand-dbcmd.drop) command, the [`dropIndexes`](https://www.mongodb.com/docs/manual/reference/command/dropIndexes.md#mongodb-dbcommand-dbcmd.dropIndexes) command, the [`validate`](https://www.mongodb.com/docs/manual/reference/command/validate.md#mongodb-dbcommand-dbcmd.validate) command; and - replication synchronization activities. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Consider the following example which sets the `quiet` parameter to `1`: ```javascript db.adminCommand( { setParameter: 1, quiet: 1 } ) ``` **See also:** [`systemLog.quiet`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.quiet) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean **Note: Enterprise Feature** Available in MongoDB Enterprise only. Configure the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) to redact any message accompanying a given log event before logging. This prevents the program from writing potentially sensitive data stored on the database to the diagnostic log. Metadata such as error or operation codes, line numbers, and source file names are still visible in the logs. Use [`redactClientLogData`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.redactClientLogData) in conjunction with [Encryption at Rest](https://www.mongodb.com/docs/manual/core/security-encryption-at-rest.md) and [TLS/SSL (Transport Encryption)](https://www.mongodb.com/docs/manual/core/security-transport-encryption.md) to assist compliance with regulatory requirements. To enable log redaction at startup, you can either: - Start [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) with the [`--redactClientLogData`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--redactClientLogData) option: ```javascript mongod --redactClientLogData ``` - Set the [`security.redactClientLogData`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.redactClientLogData) option in the [configuration file:](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options) ```yaml security: redactClientLogData: true ... ``` You can't use the [`--setParameter`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--setParameter) option to set [`redactClientLogData`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.redactClientLogData) at startup. To enable log redaction on a running `mongod` or `mongos`, use the following command: ```javascript db.adminCommand( { setParameter: 1, redactClientLogData : true } ) ``` **See also:** [`security.redactClientLogData`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.redactClientLogData) **New in version 6.1.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: `true` Configures [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-program-mongod) and [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) to redact field values of encrypted [`Binary`](https://www.mongodb.com/docs/manual/reference/mongodb-extended-json.md#mongodb-bsontype-Binary) data from all [log messages.](https://www.mongodb.com/docs/manual/reference/log-messages.md#std-label-log-messages-ref) - If the [`redactClientLogData`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.redactClientLogData) parameter or the [`security.redactClientLogData`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.redactClientLogData) setting is set to `false` and `redactEncryptedFields` is set to `true` (the default), encrypted fields are redacted from all log messages. - If the [`redactClientLogData`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.redactClientLogData) parameter or [`security.redactClientLogData`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-security.redactClientLogData) setting is set to `true`, all fields are redacted, regardless of the `redactEncryptedFields` setting. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false By default, a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) or [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) with [TLS/SSL enabled](https://www.mongodb.com/docs/manual/tutorial/configure-ssl.md#std-label-configure-mongod-mongos-for-tls-ssl) and `net.ssl.allowConnectionsWithoutCertificates` : `true` lets clients connect without providing a certificate for validation while logging an warning. Set `suppressNoTLSPeerCertificateWarning` to `1` or `true` to suppress those warnings. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following operation sets `suppressNoTLSPeerCertificateWarning` to `true`: ```bash db.adminCommand( { setParameter: 1, suppressNoTLSPeerCertificateWarning: true} ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Configures [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) to log full source code stack traces for every database and socket C++ exception, for use with debugging. If `true`, [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) will log full stack traces. This parameter is only available at runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. Consider the following example which sets the `traceExceptions` to `true`: ```javascript db.adminCommand( { setParameter: 1, traceExceptions: true } ) ``` **See also:** [`systemLog.traceAllExceptions`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.traceAllExceptions) ### Diagnostic Parameters To facilitate analysis of the MongoDB server behavior by MongoDB engineers, MongoDB logs server statistics to diagnostic files at periodic intervals. For [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), the diagnostic data files are stored in the `diagnostic.data` directory under the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance's `--dbpath` or [`storage.dbPath`.](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.dbPath) For [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), the diagnostic data files, by default, are stored in a directory under the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance's `--logpath` or [`systemLog.path`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.path) directory. The diagnostic data directory is computed by truncating the logpath's file extension(s) and concatenating `diagnostic.data` to the remaining name. For example, if [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) has `--logpath /var/log/mongodb/mongos.log.201708015`, then the diagnostic data directory is `/var/log/mongodb/mongos.diagnostic.data/` directory. To specify a different diagnostic data directory for [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), set the [`diagnosticDataCollectionDirectoryPath`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.diagnosticDataCollectionDirectoryPath) parameter. The following parameters support diagnostic data capture (FTDC): **Note:** The default values for the diagnostic data capture interval and the maximum sizes are configured to provide data to MongoDB engineers with minimal impact on performance and storage size. Typically, these values need modification only when requested by MongoDB engineers for specific diagnostic purposes. [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: String **Warning:** If [Full Time Diagnostic Data Capture (FTDC)](https://www.mongodb.com/docs/manual/administration/full-time-diagnostic-data-capture.md#std-label-ftdc-stub) is disabled with [`diagnosticDataCollectionEnabled`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.diagnosticDataCollectionEnabled) or if [`systemLog.destination`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.destination) is set to `syslog`, you must restart [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) after setting `diagnosticDataCollectionDirectoryPath`. Specify the directory for the diagnostic directory for [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos). If the directory does not exist, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) creates the directory. If unspecified, the diagnostic data directory is computed by truncating the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance's `--logpath` or [`systemLog.path`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-systemLog.path) file extension(s) and concatenating `diagnostic.data`. For example, if [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) has `--logpath /var/log/mongodb/mongos.log.201708015`, then the diagnostic data directory is `/var/log/mongodb/mongos.diagnostic.data/`. If the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) cannot create the specified directory, the diagnostic data capture is disabled for that instance. [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) may not be able to create the specified directory if a file with the same name already exists in the path or if the process does not have permissions to create the directory. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: `500` Specifies the maximum size, in megabytes, of the `diagnostic.data` directory. If directory size exceeds this number, the oldest diagnostic files in the directory are automatically deleted based on the timestamp in the file name. The minimum value for `diagnosticDataCollectionDirectorySizeMB` is `10` megabytes. `diagnosticDataCollectionDirectorySizeMB` must be greater than maximum diagnostic file size [`diagnosticDataCollectionFileSizeMB`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.diagnosticDataCollectionFileSizeMB) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the maximum size of the directory to `650` megabytes: ```bash mongod --setParameter diagnosticDataCollectionDirectorySizeMB=650 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, diagnosticDataCollectionDirectorySizeMB: 650 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true Determines whether to enable the collecting and logging of data for diagnostic purposes. Diagnostic logging is enabled by default. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following disables the diagnostic collection: ```bash mongod --setParameter diagnosticDataCollectionEnabled=false ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 Specifies the maximum size, in megabytes, of each diagnostic file. If the file exceeds the maximum file size, MongoDB creates a new file. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the maximum size of each diagnostic file to `20` megabytes: ```bash mongod --setParameter diagnosticDataCollectionFileSizeMB=20 ``` The minimum value for [`diagnosticDataCollectionFileSizeMB`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.diagnosticDataCollectionFileSizeMB) is `1` megabyte. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 1000 Specifies the interval, in milliseconds, at which to collect diagnostic data. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the interval to `5000` milliseconds or 5 seconds: ```bash mongod --setParameter diagnosticDataCollectionPeriodMillis=5000 ``` The minimum value for [`diagnosticDataCollectionPeriodMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.diagnosticDataCollectionPeriodMillis) is `100` milliseconds. ### Replication and Consistency **New in version 5.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false Specifies whether the replica set allows the use of multiple arbiters. The use of multiple arbiters is not recommended: - Multiple arbiters prevent the reliable use of the majority write concern. MongoDB counts arbiters in calculating a membership majority, but arbiters do not store data. With the inclusion of multiple arbiters, it's possible for a majority write operation to return success before the write replicates to a majority of data bearing nodes. - Multiple arbiters allow replica sets to accept writes even when the replica set doesn't have sufficient secondaries for data replication. For more information, see [Concerns with Multiple Arbiters.](https://www.mongodb.com/docs/manual/core/replica-set-arbiter.md#std-label-rollbacks-multi-arbiters) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter allowMultipleArbiters=true ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 5 The minimum latency improvement, in milliseconds, that a candidate [sync source](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-replication-sync-source-selection) must have over the current sync source before a secondary considers switching to it. A lower value makes secondaries more sensitive to small latency differences, which increases the number of sync source changes. A higher value reduces switching between candidates with similar latency. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set [`changeSyncSourceThresholdMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.changeSyncSourceThresholdMillis) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to `200` using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command within [`mongosh`:](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) ```javascript db.adminCommand( { setParameter: 1, changeSyncSourceThresholdMillis: 200 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10000 Sets the connection timeout, in milliseconds, for the [replica set monitor.](https://www.mongodb.com/docs/manual/administration/monitoring.md#std-label-replica-set-monitoring) This parameter is only available at startup. If you set this parameter, it must be greater than or equal to 500. The following example sets `connectTimeoutMs` for a `mongod` instance to 700 milliseconds: ```bash mongod --setParameter connectTimeoutMs=700 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true Flag that determines whether MongoDB creates [rollback files](https://www.mongodb.com/docs/manual/core/replica-set-rollbacks.md#std-label-rollback-data-files) that contains documents affected during a rollback. By default, [`createRollbackDataFiles`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.createRollbackDataFiles) is `true` and MongoDB creates the rollback files. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`createRollbackDataFiles`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.createRollbackDataFiles) to false so that the rollback files are not created: ```javascript mongod --setParameter createRollbackDataFiles=false ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, createRollbackDataFiles: false } ) ``` For more information, see [Collect Rollback Data.](https://www.mongodb.com/docs/manual/core/replica-set-rollbacks.md#std-label-rollback-data-files) **New in version 5.0.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false To configure cluster nodes for split horizon DNS, use host names instead of IP addresses. Starting in MongoDB v5.0, [`replSetInitiate`](https://www.mongodb.com/docs/manual/reference/command/replSetInitiate.md#mongodb-dbcommand-dbcmd.replSetInitiate) and [`replSetReconfig`](https://www.mongodb.com/docs/manual/reference/command/replSetReconfig.md#mongodb-dbcommand-dbcmd.replSetReconfig) reject configurations that use IP addresses instead of hostnames. Use [`disableSplitHorizonIPCheck`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.disableSplitHorizonIPCheck) to modify nodes that cannot be updated to use host names. The parameter only applies to the configuration commands. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) and [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) do not rely on `disableSplitHorizonIPCheck` for validation at startup. Legacy `mongod` and `mongos` instances that use IP addresses instead of host names can start after an upgrade. Instances that are configured with IP addresses log a warning to use host names instead of IP addresses. To allow configuration changes using IP addresses, set `disableSplitHorizonIPCheck=true` using the command line: ```javascript /usr/local/bin/mongod --setParameter disableSplitHorizonIPCheck=true -f /etc/mongod.conf ``` This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```javascript setParameter: disableSplitHorizonIPCheck: true ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true Enables or disables the mechanism that controls the rate at which the primary applies its writes with the goal of keeping the secondary members' [`majority committed`](https://www.mongodb.com/docs/manual/reference/command/replSetGetStatus.md#mongodb-data-replSetGetStatus.optimes.lastCommittedOpTime) lag under a configurable maximum value. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 5.0.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false If [`enableOverrideClusterChainingSetting`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.enableOverrideClusterChainingSetting) is `true`, replica set [secondary](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-secondary) members can replicate data from other secondary members even if [`settings.chainingAllowed`](https://www.mongodb.com/docs/manual/reference/replica-configuration.md#mongodb-rsconf-rsconf.settings.chainingAllowed) is `false`. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`enableOverrideClusterChainingSetting`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.enableOverrideClusterChainingSetting) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to `true`: ```bash mongod --setParameter enableOverrideClusterChainingSetting=true ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 The target maximum [`majority committed`](https://www.mongodb.com/docs/manual/reference/command/replSetGetStatus.md#mongodb-data-replSetGetStatus.optimes.lastCommittedOpTime) lag when running with flow control. When flow control is enabled, the mechanism attempts to keep the [`majority committed`](https://www.mongodb.com/docs/manual/reference/command/replSetGetStatus.md#mongodb-data-replSetGetStatus.optimes.lastCommittedOpTime) lag under the specified seconds. The parameter has no effect if flow control is disabled. The specified value must be greater than 0. In general, the default settings should suffice; however, if modifying from the default value, decreasing, rather than increasing, the value may prove to be more useful. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 The amount of time to wait to log a warning once the flow control mechanism detects the majority commit point has not moved. The specified value must be greater than or equal to 0, with 0 to disable warnings. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10000 When [`replicaSetMonitorProtocol`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replicaSetMonitorProtocol) is set to `'sdam'`, `heartBeatFrequencyMs` determines how long, in milliseconds, to wait between [`hello`](https://www.mongodb.com/docs/manual/reference/command/hello.md#mongodb-dbcommand-dbcmd.hello) requests. When [`replicaSetMonitorProtocol`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replicaSetMonitorProtocol) is set to `'streamable'`, `heartBeatFrequencyMs` determines how long, in milliseconds, to wait between [`hello`](https://www.mongodb.com/docs/manual/reference/command/hello.md#mongodb-dbcommand-dbcmd.hello) round trip time (RTT) measurements. RTT measurements are used in [server selection.](https://www.mongodb.com/docs/manual/core/read-preference-mechanics.md#std-label-replica-set-read-preference-behavior) This parameter is only available at startup. If you set this parameter, it must be greater than or equal to 500. The following example sets `heartBeatFrequencyMs` in a `mongod` instance to 700 milliseconds: ```bash mongod --setParameter heartBeatFrequencyMs=700 ``` **New in version 8.2** (and 8.0.13, 7.0.26) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: double *Default*: 10.0 The percentage of system memory that MongoDB allocates for index builds during [initial sync](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync). The amount of system memory used is bound by the values of [`initialSyncIndexBuildMemoryMinMB`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncIndexBuildMemoryMinMB) and [`initialSyncIndexBuildMemoryMaxMB`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncIndexBuildMemoryMaxMB) You can specify a value between `0.0` and `80.0`, inclusive. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the `initialSyncIndexBuildMemoryPercentage` for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 40%: ```bash mongod --setParameter initialSyncIndexBuildMemoryPercentage=40 ``` **New in version 8.2** (and 8.0.13, 7.0.26) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 16384 The maximum amount of system memory, in megabytes, that MongoDB can use for index builds during [initial sync.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync) You can specify a value between `50` and `10000000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the `initialSyncIndexBuildMemoryMaxMB` for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 20000 MB: ```bash mongod --setParameter initialSyncIndexBuildMemoryMaxMB=20000 ``` **New in version 8.2** (and 8.0.13, 7.0.26) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Integer *Default*: 200 The minimum amount of system memory, in megabytes, that MongoDB can use for index builds during [initial sync.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync) You can specify a value between `50` and `10000000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the `initialSyncIndexBuildMemoryMinMB` for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 60 MB: ```bash mongod --setParameter initialSyncIndexBuildMemoryMinMB=60 ``` **New in version 5.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: String *Default*: `logical` Available only in MongoDB Enterprise. Method used for [initial sync.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync) Set to `logical` to use [logical initial sync](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync-logical). Set to `fileCopyBased` to use [file copy based initial sync.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync-file-copy-based) This parameter only affects the sync method for the member on which it is specified. Setting this parameter on a single replica set member does not affect the sync method of any other replica set members. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. If the [`initialSyncMethod`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncMethod) parameter for the cluster is `fileCopyBased`, then there is no impact on change stream listeners. If `initialSyncMethod` is `logical` and a change stream is opened on a newly synchronized node and reads events from a point in time earlier than the completion of the logical initial sync, the pre- and post-images may be missing. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: String The preferred source for performing [initial sync](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync). Specify one of the following read preference modes: - [`primary`](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-primary) - [`primaryPreferred`](https://www.mongodb.com/docs/manual/core/read-preference.md#mongodb-readmode-primaryPreferred) (Default for voting replica set members) - [`secondary`](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-secondary) - [`secondaryPreferred`](https://www.mongodb.com/docs/manual/core/read-preference.md#mongodb-readmode-secondaryPreferred) - [`nearest`](https://www.mongodb.com/docs/manual/core/read-preference.md#mongodb-readmode-nearest) (Default for newly added *or* non-voting replica set members) If the replica set has disabled [`chaining`](https://www.mongodb.com/docs/manual/reference/replica-configuration.md#mongodb-rsconf-rsconf.settings.chainingAllowed), the default [`initialSyncSourceReadPreference`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncSourceReadPreference) read preference mode is [`primary`.](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-primary) You cannot specify a tag set or `maxStalenessSeconds` to [`initialSyncSourceReadPreference`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncSourceReadPreference) If the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) cannot find a sync source based on the specified read preference, it logs an error and restarts the initial sync process. The [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) exits with an error if it cannot complete the initial sync process after `10` attempts. For more information on sync source selection, see [Initial Sync Source Selection.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-initial-sync-source-selection) [`initialSyncSourceReadPreference`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.initialSyncSourceReadPreference) takes precedence over the replica set's [`settings.chainingAllowed`](https://www.mongodb.com/docs/manual/reference/replica-configuration.md#mongodb-rsconf-rsconf.settings.chainingAllowed) setting when selecting an initial sync source. After a replica set member successfully completes initial sync, it defers to the value of [`chainingAllowed`](https://www.mongodb.com/docs/manual/reference/replica-configuration.md#mongodb-rsconf-rsconf.settings.chainingAllowed) when selecting a replication sync source. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 86400 The amount of time in seconds a secondary performing initial sync attempts to resume the process if interrupted by a transient network error. The default value is equivalent to 24 hours. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 30 **Warning: For testing purposes only** This parameter is intended for testing purposes only and not for production use. The time in minutes that a [session](https://www.mongodb.com/docs/manual/core/read-isolation-consistency-recency.md#std-label-sessions) remains active after its most recent use. Sessions that have not received a new read/write operation from the client or been refreshed with [`refreshSessions`](https://www.mongodb.com/docs/manual/reference/command/refreshSessions.md#mongodb-dbcommand-dbcmd.refreshSessions) within this threshold are cleared from the cache. State associated with an expired session may be cleaned up by the server at any time. This parameter applies only to the instance on which it is set. To set this parameter on replica sets and sharded clusters, you must specify the same value on every member; otherwise, sessions will not function properly. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`localLogicalSessionTimeoutMinutes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.localLogicalSessionTimeoutMinutes) for a test [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 20 minutes: ```bash mongod --setParameter localLogicalSessionTimeoutMinutes=20 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 15 Defines the length of the latency window used in [server selection](https://www.mongodb.com/docs/manual/core/read-preference-mechanics.md#std-label-replica-set-read-preference-behavior) in milliseconds. This parameter is only available at startup. If you set this parameter, it must be greater than or equal to 0. The following example sets `localThresholdMs` for a `mongod` instance to 20 milliseconds: ```bash mongod --setParameter localThresholdMs=20 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 300000 (5 minutes) The interval (in milliseconds) at which the cache refreshes its logical session records against the main session store. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`logicalSessionRefreshMillis`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.logicalSessionRefreshMillis) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 10 minutes: ```bash mongod --setParameter logicalSessionRefreshMillis=600000 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 31536000 (1 year) The maximum amount by which the current cluster time can be advanced; specifically, [`maxAcceptableLogicalClockDriftSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxAcceptableLogicalClockDriftSecs) is the maximum difference between the new value of the cluster time and the current cluster time. Cluster time is a logical time used for ordering of operations. You cannot advance the cluster time to a new value if the new cluster time differs from the current cluster time by more than [`maxAcceptableLogicalClockDriftSecs`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxAcceptableLogicalClockDriftSecs) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`maxAcceptableLogicalClockDriftSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxAcceptableLogicalClockDriftSecs) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 15 minutes: ```bash mongod --setParameter maxAcceptableLogicalClockDriftSecs=900 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 5.0** *Type*: integer *Default*: 3 [Sync sources](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-replication-sync-source-selection) are evaluated each time a sync source is updated and each time a node fetches a batch of oplog entries. If there are more than `maxNumSyncSourceChangesPerHour` source changes in an hour, the node temporarily stops re-evaluating that sync source. If this parameter is set with a high value, the node may make unnecessary source changes. This parameter will not prevent a node from starting to sync from another node if it doesn't have a sync source. The node will re-evaluate if a sync source becomes invalid. Similarly, if the primary changes and chaining is disabled, the node will update to sync from the new primary. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 1000000 The maximum number of sessions that can be cached. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`maxSessions`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxSessions) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 1000: ```bash mongod --setParameter maxSessions=1000 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 30 The maximum lag, in seconds, that a candidate [sync source](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-replication-sync-source-selection) can have relative to the newest oplog entry on the primary and still qualify as an eligible sync source. If a candidate's most recent oplog entry is more than [`maxSyncSourceLagSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxSyncSourceLagSecs) seconds behind the primary, MongoDB rejects it as a sync source. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set [`maxSyncSourceLagSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.maxSyncSourceLagSecs) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to `20`: ```bash mongod --setParameter maxSyncSourceLagSecs=20 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Document *Default*: `{ samplingRate: 0.01, maxTimeMS: 1000 }` Specifies the settings for [mirrored reads](https://www.mongodb.com/docs/manual/replication.md#std-label-mirrored-reads) for the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. The settings only take effect when the member is a primary. The parameter [`mirrorReads`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.mirrorReads) takes a JSON document with the following fields: | Field | Description | | --- | --- | | `samplingRate` | The sampling rate used to mirror a subset of [operations that support mirroring](https://www.mongodb.com/docs/manual/replication.md#std-label-mirrored-reads-supported-operations) to a subset of electable (specifically, [`priority greater than 0`](https://www.mongodb.com/docs/manual/reference/replica-configuration.md#mongodb-rsconf-rsconf.members-n-.priority)) secondaries. That is, the primary mirrors reads to each electable secondary at the specified sampling rate. Valid values are: `0.0`Turns off mirroring.`1.0`The primary mirrors all [operations that support mirroring](https://www.mongodb.com/docs/manual/replication.md#std-label-mirrored-reads-supported-operations) to each electable secondary.Number between `0.0` and `1.0` (exclusive)The primary randomly samples each electable secondary at the specified rate to be sent mirrored reads. For example, given a replica set with a primary and two electable secondaries and a sampling rate of `0.10`, the primary mirrors reads to each electable secondary at the sampling rate of 10 percent such that one read may be mirrored to one secondary and not to the other or to both or to neither. That is, if the primary receives `100` operations that can be mirrored, the sampling rate of `0.10` may result in `8` reads being mirrored to one secondary and `13` reads to the other or `10` to each, etc. The default value is `0.01`. | | `maxTimeMS` | The maximum time in milliseconds for the mirrored reads. The default value is `1000`. The `maxTimeMS` for the mirrored reads is separate from the `maxTimeMS` of the original read being mirrored. | | `targetedMirroring` | Contains fields to configure how you target specific nodes for cache warming. For more information on targeted mirroring, see [Targeted Mirrored Reads.](https://www.mongodb.com/docs/manual/replication.md#std-label-targeted-mirrored-reads) Includes the following fields: `tag`Defaults to an empty `BSONObj`. The [replica set tag](https://www.mongodb.com/docs/manual/tutorial/configure-replica-set-tag-sets.md#std-label-replica-set-configuration-tag-sets) that you can use to target nodes for mirroring. You can configure a node for targeted mirroring using the following syntax:`tag: { "": "" }`You can only supply one tag. All nodes within the same replica set that have these tags are targeted.`samplingRate`*Type*: Float*Range*: `0.0` to `1.0` (inclusive)The rate at which targeted reads are mirrored to the host or hosts. A rate of `0.0` means no reads are mirrored, and a rate of `1.0` means all reads are mirrored. Although `samplingRate` defaults to `0.01`, the `targetedMirroring` feature is off by default, since the `tag` field defaults to empty.`maxTimeMS`*Type*: intThe maximum time in milliseconds before the mirrored read times out. The minimum value for `maxTimeMS` is `0`. Defaults to `1000`. | This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. If you specify from the configuration file or on the command line, **enclose the** `mirrorReads` **document in quotes**. For example, the following sets the mirror reads sampling rate to `0.10` from the command line: ```bash mongod --setParameter mirrorReads='{ samplingRate: 0.10 }' ``` Or, to specify in a configuration file: ```yaml setParameter: mirrorReads: '{samplingRate: 0.10}' ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), do **not** enclose the document in quotes: ```javascript db.adminCommand( { setParameter: 1, mirrorReads: { samplingRate: 0.10 } } ) ``` **New in version 8.2** *Type*: int *Default*: 4 Controls the maximum number of connections in the mirroring pool. This parameter affects both [general](https://www.mongodb.com/docs/manual/replication.md#std-label-mirrored-reads) and [targeted](https://www.mongodb.com/docs/manual/replication.md#std-label-targeted-mirrored-reads) mirrored reads. `mirrorReadsMaxConnPoolSize` has a minimum value of 1. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 6.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 0 The number of milliseconds to delay applying batches of oplog operations on secondary nodes. By default, `oplogBatchDelayMillis` is `0`, meaning oplog batches are applied with no delay. When there is no delay, MongoDB may apply frequent, small oplog batches to secondaries. Increasing `oplogBatchDelayMillis` causes MongoDB to apply oplog batches less frequently on secondaries, with each batch containing larger amounts of data. This reduces IOPS (Input/Output Operations Per Second) on secondaries, but adds latency for writes with write concern [`"majority"`.](https://www.mongodb.com/docs/manual/reference/write-concern.md#mongodb-writeconcern-writeconcern.-majority-) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, run the following command to set the `oplogBatchDelayMillis` for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 20 milliseconds: ```bash mongod --setParameter oplogBatchDelayMillis=20 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true Enables or disables [streaming replication](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-streaming-replication). Set the value to `true` to enable streaming replication. Set the value to `false` to disable streaming replication. If disabled, secondaries fetch batches of [oplog](https://www.mongodb.com/docs/manual/core/replica-set-oplog.md#std-label-replica-set-oplog) entries by issuing a request to their *sync from* source and waiting for a response. This requires a network roundtrip for each batch of [oplog](https://www.mongodb.com/docs/manual/core/replica-set-oplog.md) entries. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 60 Maximum time in seconds for a member of a [replica set](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-replica-set) to wait for the [`find`](https://www.mongodb.com/docs/manual/reference/command/find.md#mongodb-dbcommand-dbcmd.find) command to finish during [data synchronization.](https://www.mongodb.com/docs/manual/core/replica-set-sync.md#std-label-replica-set-sync) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 The duration in seconds between [noop](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-noop) writes on each individual node. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **Note:** To modify this value for a [MongoDB Atlas](https://www.mongodb.com/docs/atlas/) cluster, you must contact [Atlas Support.](https://www.mongodb.com/docs/atlas/support/) The following example sets the `periodicNoopIntervalSecs` to 1 second at startup: ```javascript mongod --setParameter periodicNoopIntervalSecs=1 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 104857600 (100MB) Sets the maximum oplog application batch size in bytes. Values can range from 16777216 (16MB) to 104857600 (100MB) inclusive. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`replBatchLimitBytes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replBatchLimitBytes) to 64 MB to limit the oplog application batch size: ```javascript mongod --setParameter replBatchLimitBytes=67108864 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, replBatchLimitBytes: 64 * 1024 * 1024 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: string *Default*: "streamable" Determines which replica set monitor protocol to use. You can set this parameter to `"streamable"`, which is compliant with [Server Discovery and Monitoring (SDAM)](https://github.com/mongodb/specifications/blob/master/source/server-discovery-and-monitoring/server-discovery-and-monitoring.md) specification and allows for constant [`hello`](https://www.mongodb.com/docs/manual/reference/command/hello.md#mongodb-dbcommand-dbcmd.hello) requests. You can also set this parameter to `"sdam"`, which is compliant with SDAM specification. This parameter is only available at startup. The following example sets `replicaSetMonitorProtocol` to `"sdam"` on a `mongod` instance: ```bash mongod --setParameter replicaSetMonitorProtocol='sdam' ``` **New in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 0 Minimum number of threads to use to apply replicated operations in parallel. Values can range from 0 to 256 inclusive. Parallel application of replication operations uses up to [`replWriterThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount) threads. If [`replWriterMinThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) is configured with a value less than [`replWriterThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount), the thread pool will timeout idle threads until the total count of threads in the thread pool is equal to [`replWriterMinThreadCount`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) [`replWriterMinThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) must be less than or equal to [`replWriterThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount). MongoDB rejects the update if you set [`replWriterMinThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) to a value greater than [`replWriterThreadCount`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 16 Maximum number of threads to use to apply replicated operations in parallel. Values can range from 1 to 256 inclusive. However, the maximum number of threads used is capped at twice the number of available cores. [`replWriterThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount) must be greater than or equal to [`replWriterMinThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount). MongoDB rejects the update if you set [`replWriterThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterThreadCount) to a value less than [`replWriterMinThreadCount`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** [`replWriterMinThreadCount`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.replWriterMinThreadCount) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: 64-bit integer *Default*: 86400 (1 day) Maximum age of data that can be rolled back. Negative values for this parameter are not valid. If the time between the end of the to-be-rolledback instance's oplog and the first operation after the common point (the last point where the source node and the to-be-rolledback node had the same data) exceeds this value, the rollback will fail. To effectively have an unlimited rollback period, set the value to `2147483647` which is the maximum value allowed and equivalent to roughly 68 years. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 30 The minimum lifetime a transaction record exists in the [`transactions`](https://www.mongodb.com/docs/manual/reference/config-database.md#mongodb-data-config.transactions) collection before the record becomes eligible for cleanup. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the [`TransactionRecordMinimumLifetimeMinutes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.TransactionRecordMinimumLifetimeMinutes) for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance to 20 minutes: ```bash mongod --setParameter TransactionRecordMinimumLifetimeMinutes=20 ``` **See also:** [`localLogicalSessionTimeoutMinutes`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.localLogicalSessionTimeoutMinutes) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 The length of time (in milliseconds) that a secondary must wait if the `afterClusterTime` is greater than the last applied time from the oplog. After the `waitForSecondaryBeforeNoopWriteMS` passes, if the `afterClusterTime` is still greater than the last applied time, the secondary makes a no-op write to advance the last applied time. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the [`waitForSecondaryBeforeNoopWriteMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.waitForSecondaryBeforeNoopWriteMS) to 20 milliseconds: ```bash mongod --setParameter waitForSecondaryBeforeNoopWriteMS=20 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, waitForSecondaryBeforeNoopWriteMS: 20 } ) ``` ### Sharding Parameters **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10000000 If `sampleRate` and `sampleSize` are not set when you run `analyzeShardKey`, specifies the number of documents to sample when calculating shard key characteristics metrics. Must be greater than `0`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `analyzeShardKeyCharacteristicsDefaultSampleSize` to `10000` at startup: ```bash mongod --setParameter analyzeShardKeyCharacteristicsDefaultSampleSize=10000 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, analyzeShardKeyCharacteristicsDefaultSampleSize: 10000 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: double *Default*: 0.7 Specifies the `RecordId` correlation coefficient threshold used to determine if a shard key is monotonically changing in insertion order. Must be greater than `0` and less than or equal to `1`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `analyzeShardKeyMonotonicityCorrelationCoefficientThreshold` to `1` at startup: ```bash mongod --setParameter analyzeShardKeyMonotonicityCorrelationCoefficientThreshold=1 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, analyzeShardKeyMonotonicityCorrelationCoefficientThreshold: 1 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 5 Specifies the number of most common shard key values to return. If the collection contains fewer unique shard keys than this value, `analyzeShardKeyNumMostCommonValues` returns that number of most common values. Must be greater than `0` and less than or equal to `1000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `analyzeShardKeyNumMostCommonValues` to `3` at startup: ```bash mongod --setParameter analyzeShardKeyNumMostCommonValues=3 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, analyzeShardKeyNumMostCommonValues: 3 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 100 Specifies the number of ranges to partition the shard key space into when calculating the [hotness](https://www.mongodb.com/docs/manual/core/sharding-troubleshooting-shard-keys.md#std-label-shard-hotness) of shard key ranges. Must be greater than `0` and less than or equal to `10000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `analyzeShardKeyNumRanges` to `50` at startup: ```bash mongod --setParameter analyzeShardKeyNumRanges=50 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, analyzeShardKeyNumRanges: 50 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: Non-negative integer *Default*: 10 The number of documents to sample per shard key [range](https://www.mongodb.com/docs/manual/core/sharding-choose-a-shard-key.md#std-label-shard-key-range). Must be a value greater than zero and less than or equal to `10000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `analyzeShardKeyNumSamplesPerRange` to `50` at startup: ```bash mongod --setParameter analyzeShardKeyNumSamplesPerRange=50 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, analyzeShardKeyNumSamplesPerRange: 50 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 3600 When AutoMerger is enabled, specifies the amount of time between automerging rounds, in seconds. The default value is 3600 seconds, or one hour. `autoMergerIntervalSecs` can only be set on config servers. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `autoMergerIntervalSecs` to 7200 seconds, or two hours, at startup: ```bash mongod --setParameter autoMergerIntervalSecs=7200 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, autoMergerIntervalSecs: 7200 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 15000 When AutoMerger is enabled, specifies the minimum amount time between merges initiated by the AutoMerger on the same collection, in milliseconds. `autoMergerThrottlingMS` can only be set on config servers. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `autoMergerThrottlingMS` to 60000 milliseconds, or one minute, at startup: ```bash mongod --setParameter autoMergerThrottlingMS=60000 ``` During run time, you can set or modify the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, autoMergerThrottlingMS: 60000 } ) ``` **New in version 7.0** (*Also available starting in 6.3.1, 6.0.6, 5.0.18*) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 1000 Specifies the minimum amount of time between two consecutive balancing rounds. This allows you to throttle the balancing rate. This parameter only takes effect on config server nodes. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `balancerMigrationsThrottlingMs` to 2000 milliseconds at startup: ```bash mongod --setParameter balancerMigrationsThrottlingMs=2000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, balancerMigrationsThrottlingMs: 2000 } ) ``` **New in version 8.1** (*also available starting in 8.0.10, 7.0.22*) *Type*: integer *Default*: 10000 [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Maximum number of entries allowed in the catalog cache for collections. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 8.1** (*also available starting in 8.0.10, 7.0.22*) *Type*: integer *Default*: 10000 [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Maximum number of entries allowed in the catalog cache for databases. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 5.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 1000 Specifies the minimum time period (in milliseconds) between consecutive split and merge commands run by the [balancer](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-balancer) when the [chunks](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-chunk) in a [sharded](https://www.mongodb.com/docs/manual/sharding.md) collection are defragmented. [`chunkDefragmentationThrottlingMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.chunkDefragmentationThrottlingMS) limits the rate of split and merge commands. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`chunkDefragmentationThrottlingMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.chunkDefragmentationThrottlingMS) to `10` milliseconds: ```bash mongod --setParameter chunkDefragmentationThrottlingMS=10 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, chunkDefragmentationThrottlingMS: 10 } ) ``` **New in version 7.0.12** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true starting in MongoDB 8.0.10 When set on a sharded cluster with a single shard, enables direct connection warnings. If a user connects directly to the single-shard cluster, `mongod` logs a warning every hour and updates [`shardingStatistics.unauthorizedDirectShardOps`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.shardingStatistics.unauthorizedDirectShardOps) with unauthorized direct shard operations. To avoid this, users should connect to single-shard clusters through a router, like `mongos`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: false If set on a shard's primary, specifies if MongoDB pauses range deletion on the shard. If set to `true`, MongoDB pauses cleanup of [ranges](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-range) containing [orphaned documents](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-orphaned-document). The shard can continue to donate chunks to other shards, but the shard does not remove donated documents until you set this parameter to `false`. This shard can continue to receive chunks from other shards as long as it does not have a pending range deletion task in the [`config.rangeDeletions`](https://www.mongodb.com/docs/manual/reference/config-database.md#mongodb-data-config.rangeDeletions) collection that overlaps with the incoming chunk's range. When [`disableResumableRangeDeleter`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.disableResumableRangeDeleter) is `true`, chunk migrations fail if [orphaned documents](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-orphaned-document) exist on the recipient shard's primary in the same range as the incoming chunks. The parameter has no effect on the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) if it is not the shard's primary. **Important:** If you set [`disableResumableRangeDeleter`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.disableResumableRangeDeleter) parameter to `true`, ensure that you apply it consistently for all members in the shard's replica set. In the event of a failover, this setting's value on the new primary dictates the behavior of the range deleter. Starting in MongoDB 8.0, you can set `disableResumableRangeDeleter` during both startup and run time. To set `disableResumableRangeDeleter` at startup, use the following command: ```javascript mongod --setParameter disableResumableRangeDeleter=false ``` To set `disableResumableRangeDeleter` during run time, use the following command: ```javascript db.adminCommand( { setParameter: 1, disableResumableRangeDeleter: false } ) ``` **Note: Deprecated in 8.0** Starting in MongoDB 8.0, the parameter is deprecated and doesn't cause any changes or errors. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true This parameter allows the catalog cache to be refreshed only if the shard needs to be refreshed. If disabled, any stale chunk will cause the entire chunk distribution for a collection to be considered stale and force all [routers](https://www.mongodb.com/docs/manual/core/sharded-cluster-query-router.md#std-label-sharded-cluster-query-routing) who contact the shard to refresh their shard catalog cache. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter enableFinerGrainedCatalogCacheRefresh=true mongos --setParameter enableFinerGrainedCatalogCacheRefresh=true ``` **See also:** - [Sharding](https://www.mongodb.com/docs/manual/sharding.md#std-label-sharding-background) - [`shardingStatistics.catalogCache`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.shardingStatistics.catalogCache) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: boolean *Default*: true If set on the config server's primary, enables or disables the index consistency check for sharded collections. The parameter has no effect on the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) if it is not the config server's primary. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`enableShardedIndexConsistencyCheck`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.enableShardedIndexConsistencyCheck) to `false` for a config server primary: ```javascript mongod --setParameter enableShardedIndexConsistencyCheck=false ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, enableShardedIndexConsistencyCheck: false } ) ``` **See also:** - [`shardedIndexConsistencyCheckIntervalMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.shardedIndexConsistencyCheckIntervalMS) parameter - [`shardedIndexConsistency`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.shardedIndexConsistency) metrics returned by the [`serverStatus`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-dbcommand-dbcmd.serverStatus) command. **New in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 900000 The timeout in milliseconds for find operations on [`chunks`.](https://www.mongodb.com/docs/manual/reference/config-database.md#mongodb-data-config.chunks) If there is a large number of chunks in the cluster and chunk loading fails with the error `ExceededTimeLimit`, increase the parameter value: ```bash mongod --setParameter findChunksOnConfigTimeoutMS=1000000 ``` This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.3** Type: Non-negative integer *Default*: 20000 milliseconds The timeout in milliseconds for `find` operations against the `config.shards` namespace. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets `findShardsOnConfigTimeoutMS` to `30000` milliseconds during runtime: ```bash db.adminCommand( { setParameter: 1, findShardsOnConfigTimeoutMS: 30000 } ) ``` The following example sets `findShardsOnConfigTimeoutMS` to `30000` milliseconds at startup: ```bash mongos --setParameter findShardsOnConfigTimeoutMS=30000 ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) Type: boolean *Default*: true Configures a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance to preload the routing table for a sharded cluster on startup. With this setting enabled, the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) caches the cluster-wide routing table for each sharded collection as part of its startup procedure, before it begins accepting client connections. Without this setting enabled, the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) only loads a routing table as needed for incoming client connections, and only loads the specific routing table for the namespace of a given request. A [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance with the [`loadRoutingTableOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.loadRoutingTableOnStartup) parameter enabled may experience longer startup times, but will result in faster servicing of initial client connections once started. [`loadRoutingTableOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.loadRoutingTableOnStartup) is enabled by default. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **New in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 For [`moveChunk`](https://www.mongodb.com/docs/manual/reference/command/moveChunk.md#mongodb-dbcommand-dbcmd.moveChunk) and [`moveRange`](https://www.mongodb.com/docs/manual/reference/command/moveRange.md#mongodb-dbcommand-dbcmd.moveRange) operations, specifies the maximum percentage of untrasferred data allowed by the migration protocol (expressed in percentage of the total chunk size) to transition from the `catchup` phase to the `commit` phase. Setting a higher catchup percentage can decrease the amount of time it takes for the migration to complete at the cost of increased latency during concurrent [`upsert`](https://www.mongodb.com/docs/manual/reference/method/db.collection.updateOne.md#mongodb-method-db.collection.updateOne) and [`delete`](https://www.mongodb.com/docs/manual/reference/method/db.collection.deleteOne.md#mongodb-method-db.collection.deleteOne) operations. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Starting in MongoDB 7.1 (and 7.0.1), you can set the parameter during runtime. For example, to set the maximum percentage to 20, you can issue the following during startup: ```bash mongod --setParameter maxCatchUpPercentageBeforeBlockingWrites=20 ``` Starting in MongoDB 7.1 (and 7.0.1), you can set the parameter during runtime with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```bash db.adminCommand( { setParameter: 1, maxCatchUpPercentageBeforeBlockingWrites: 20} ) ``` **Important:** Starting in MongoDB 8.1, hedged reads are removed and this parameter has no effect. **Deprecated** **Note:** Starting in MongoDB 8.1, the old `metadataRefreshInTransactionMaxWaitBehindCritSecMS` parameter is renamed `metadataRefreshInTransactionMaxWaitMS`. You can continue to use `metadataRefreshInTransactionMaxWaitBehindCritSecMS` as the parameter name, but it is deprecated and will be removed in a future MongoDB release. **New in version 5.2** (*Also available starting in 5.1.0, 5.0.4*) **Changed in version 8.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 500 Limits the time a shard waits for a critical section within a transaction. When a query accesses a shard, a [chunk migration](https://www.mongodb.com/docs/manual/tutorial/migrate-chunks-in-sharded-cluster.md#std-label-migrate-chunks-sharded-cluster) or [DDL operation](https://www.mongodb.com/docs/manual/core/transactions-operations.md#std-label-transactions-operations-ddl) may already hold the critical section for the collection. If the query finds the critical section is taken, the shard waits until the critical section has been released. When the shard returns control to [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) retries the query. However, if a multi-shard transaction interacts with an operation that takes the critical section on multiple shards, the interaction can result in a distributed deadlock. [`metadataRefreshInTransactionMaxWaitBehindCritSecMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitBehindCritSecMS) limits the maximum time a shard waits within a transaction for the critical section to be released. To reduce the maximum wait time for the critical section within a transaction, lower the value of [`metadataRefreshInTransactionMaxWaitBehindCritSecMS`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitBehindCritSecMS) **Warning:** If [`metadataRefreshInTransactionMaxWaitBehindCritSecMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitBehindCritSecMS) is too low, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) could use all of its retry attempts and return an error. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set [`metadataRefreshInTransactionMaxWaitBehindCritSecMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitBehindCritSecMS) to 400 milliseconds: ```javascript db.adminCommand( { setParameter: 1, metadataRefreshInTransactionMaxWaitBehindCritSecMS: 400 } ) ``` **Changed in version 8.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 500 Limits the time a shard waits for a critical section within a transaction. **Note:** Starting in MongoDB 8.1, the old `metadataRefreshInTransactionMaxWaitBehindCritSecMS` parameter is renamed `metadataRefreshInTransactionMaxWaitMS`. You can continue to use `metadataRefreshInTransactionMaxWaitBehindCritSecMS` as the parameter name, but it is deprecated and will be removed in a future MongoDB release. When a query accesses a shard, a [chunk migration](https://www.mongodb.com/docs/manual/tutorial/migrate-chunks-in-sharded-cluster.md#std-label-migrate-chunks-sharded-cluster) or [DDL operation](https://www.mongodb.com/docs/manual/core/transactions-operations.md#std-label-transactions-operations-ddl) may already hold the critical section for the collection. If the query finds the critical section is taken, the shard waits until the critical section has been released. When the shard returns control to [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) retries the query. However, if a multi-shard transaction interacts with an operation that takes the critical section on multiple shards, the interaction can result in a distributed deadlock. [`metadataRefreshInTransactionMaxWaitMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitMS) limits the maximum time a shard waits within a transaction for the critical section to be released. To reduce the maximum wait time for the critical section within a transaction, lower the value of [`metadataRefreshInTransactionMaxWaitMS`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitMS) **Warning:** If [`metadataRefreshInTransactionMaxWaitMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitMS) is too low, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) could use all of its retry attempts and return an error. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set [`metadataRefreshInTransactionMaxWaitMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.metadataRefreshInTransactionMaxWaitMS) to 400 milliseconds: ```javascript db.adminCommand( { setParameter: 1, metadataRefreshInTransactionMaxWaitMS: 400 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 0 Time in milliseconds to wait between batches of insertions during cloning step of the migration process. This wait is in addition to the `secondaryThrottle`. The default value of `0` indicates no additional wait. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following sets the [`migrateCloneInsertionBatchDelayMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.migrateCloneInsertionBatchDelayMS) to 200 milliseconds: ```bash mongod --setParameter migrateCloneInsertionBatchDelayMS=200 ``` The parameter may also be set using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, migrateCloneInsertionBatchDelayMS: 200 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 0 The maximum number of documents to insert in a single batch during the cloning step of the migration process. The default value of `0` indicates no maximum number of documents per batch. However, in practice, this results in batches that contain up to 16 MB of documents. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following sets the [`migrateCloneInsertionBatchSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.migrateCloneInsertionBatchSize) to 100 documents: ```bash mongod --setParameter migrateCloneInsertionBatchSize=100 ``` The parameter may also be set using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, migrateCloneInsertionBatchSize: 100 } ) ``` **New in version 5.0** [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: integer *Default*: 15000 Specifies the time (in milliseconds) to wait for any ongoing database operations to complete before initiating a shutdown of [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) in response to a `SIGTERM` signal. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the time to 250 milliseconds, you can issue the following during startup: ```bash mongos --setParameter mongosShutdownTimeoutMillisForSignaledShutdown=250 ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ```javascript db.adminCommand( { setParameter: 1, mongosShutdownTimeoutMillisForSignaledShutdown: 250 } ) ``` **Important:** Starting in MongoDB 8.1, hedged reads are removed and this parameter has no effect. **Changed in version 8.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Default: 3600 (60 minutes) Minimum delay before a migrated [chunk](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-chunk) is deleted from the source shard. Before deleting a migrated chunk, MongoDB waits for in-progress queries involving the chunk to complete on the shard primary and then waits an additional [`orphanCleanupDelaySecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.orphanCleanupDelaySecs) seconds. Starting in 8.2, the behavior of in-progress queries on shard secondaries is determined by [`terminateSecondaryReadsOnOrphanCleanup`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.terminateSecondaryReadsOnOrphanCleanup) If a shard has storage constraints, consider reducing this value temporarily. If running queries that exceed 60 minutes on shard secondaries, consider increasing this value. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following sets the [`orphanCleanupDelaySecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.orphanCleanupDelaySecs) to 20 minutes: ```bash mongod --setParameter orphanCleanupDelaySecs=1200 ``` This may also be set using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, orphanCleanupDelaySecs: 1200 } ) ``` **Tip:** In all versions, the new value of [`orphanCleanupDelaySecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.orphanCleanupDelaySecs) is only applied to range deletions created after the value is changed. To apply the new value to existing range deletions, [force a step down.](https://www.mongodb.com/docs/manual/reference/method/rs.stepDown.md#std-label-rs.stepDown-behavior) **New in version 7.2** (and 7.1.1, 7.0.4, 6.0.13, 5.0.25) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Integer Default: 1000 To route and serve operations, shards must know the routing and ownership information associated with their collections. This information propagates from a shard's primary node to its secondary nodes through the replication of the internal cache collections `config.cache.collections` and `config.cache.chunks.`. In previous versions, updates on the chunk cache collection were performed individually (meaning that an entry was deleted and a new entry was inserted). Starting in MongoDB 7.2, these updates are performed as a batch of deletions followed by a batch of insertions. The updated logic improves performance for collections that contain a large number of chunks. The `persistedChunkCacheUpdateMaxBatchSize` parameter specifies the maximum batch size used for updating the persisted chunk cache. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets `persistedChunkCacheUpdateMaxBatchSize` to 700 at startup: ```bash mongod --setParameter persistedChunkCacheUpdateMaxBatchSize=700 ``` You can also set `persistedChunkCacheUpdateMaxBatchSize` during runtime: ```javascript db.adminCommand( { setParameter: 1, persistedChunkCacheUpdateMaxBatchSize: 700 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 7 \* 24 \* 3600 Amount of time that a sampled query document exists before being removed by the TTL monitor, in seconds. Must be greater than `0`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `queryAnalysisSampleExpirationSecs` to `691200` (`8 * 24 * 3600`) at startup on a `mongod` instance: ```bash mongod --setParameter queryAnalysisSampleExpirationSecs=691200 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, queryAnalysisSampleExpirationSecs: 691200 } ) ``` **New in version 7.0** **Changed in version 7.0.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 10 Interval that a sampler (`mongos` or `mongod`) refreshes its query analyzer sample rates. The sample rate configured by the `configureQueryAnalyzer` command is divided among `mongos` instances in the sharded cluster or `mongod` instances in the replica set based on the traffic going through them. To make the sample rate assignment for a `mongos` or `mongod` more responsive to the traffic going through it, decrease this value. We recommend using the default value. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Starting in MongoDB 7.0.1, you can set `queryAnalysisSamplerConfigurationRefreshSecs` during run time. This example sets `queryAnalysisSamplerConfigurationRefreshSecs` to 60 seconds at startup on a `mongod` instance: ```bash mongod --setParameter queryAnalysisSamplerConfigurationRefreshSecs=60 ``` This example sets `queryAnalysisSamplerConfigurationRefreshSecs` to 60 seconds at startup on a `mongos` instance: ```bash mongos --setParameter queryAnalysisSamplerConfigurationRefreshSecs=60 ``` To set the value to 30 seconds, run the following: ```javascript db.adminCommand( { setParameter: 1, queryAnalysisSamplerConfigurationRefreshSecs: 30 } ) ``` **New in version 7.0** **Changed in version 7.0.1** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 90 Interval that sampled queries are written to disk, in seconds. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Starting in MongoDB 7.0.1, you can set `queryAnalysisWriterIntervalSecs` during run time. This example sets `queryAnalysisWriterIntervalSecs` to 60 seconds at startup on a `mongod` instance: ```bash mongod --setParameter queryAnalysisWriterIntervalSecs=60 ``` To set the value to 60 seconds, run the following: ```javascript db.adminCommand( { setParameter: 1, queryAnalysisWriterIntervalSecs: 60 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 100000 Maximum number of sampled queries to write to disk at once. Must be greater than `0` and less than or equal to `100000`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `queryAnalysisWriterMaxBatchSize` to `1000` at startup on a `mongod` instance: ```bash mongod --setParameter queryAnalysisWriterMaxBatchSize=1000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, queryAnalysisWriterMaxBatchSize: 1000 } ) ``` **New in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 100 \* 1024 \* 1024 Maximum amount of memory in bytes that the query sampling writer is allowed to use. Once the limit is reached, all new queries and diffs are discarded from sampling until the buffer is flushed. Must be greater than `0`. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. This example sets `queryAnalysisWriterMaxMemoryUsageBytes` to `10000000` at startup on a `mongod` instance: ```bash mongod --setParameter queryAnalysisWriterMaxMemoryUsageBytes=10000000 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 20 The amount of time in milliseconds to wait before the next batch of deletion during the cleanup stage of [range migration.](https://www.mongodb.com/docs/manual/core/sharding-balancer-administration.md#std-label-range-migration-procedure) The [\_secondaryThrottle replication delay](https://www.mongodb.com/docs/manual/core/sharding-balancer-administration.md#std-label-chunk-migration-replication) occurs after each batch deletion. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following sets the [`rangeDeleterBatchDelayMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.rangeDeleterBatchDelayMS) to 200 milliseconds: ```bash mongod --setParameter rangeDeleterBatchDelayMS=200 ``` The parameter may also be set using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, rangeDeleterBatchDelayMS: 200 } ) ``` **Tip:** In versions prior to 6.0.3, the new value of [`rangeDeleterBatchDelayMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.rangeDeleterBatchDelayMS) is only applied to range deletions created after the value is changed. To apply the new value to existing range deletions, [force a step down.](https://www.mongodb.com/docs/manual/reference/method/rs.stepDown.md#std-label-rs.stepDown-behavior) From 6.0.3 on, the new value of the parameter is applied to all the range deletions processed after the update, regardless of when the range deletion was created. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 2147483647 starting in MongoDB 5.1.2 and 5.0.6 The maximum number of documents in each batch to delete during the cleanup stage of [range migration.](https://www.mongodb.com/docs/manual/core/sharding-balancer-administration.md#std-label-range-migration-procedure) A value of `0` indicates that the system chooses the default value. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`rangeDeleterBatchSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.rangeDeleterBatchSize) to 32 documents: ```bash mongod --setParameter rangeDeleterBatchSize=32 ``` The parameter may also be set using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, rangeDeleterBatchSize: 32 } ) ``` **Tip:** In versions prior to 6.0.3, the new value of [`rangeDeleterBatchSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.rangeDeleterBatchSize) is only applied to range deletions created after the value is changed. To apply the new value to existing range deletions, [force a step down.](https://www.mongodb.com/docs/manual/reference/method/rs.stepDown.md#std-label-rs.stepDown-behavior) From 6.0.3 on, the new value of the parameter is applied to all the range deletions processed after the update, regardless of when the range deletion was created. **Important:** Starting in MongoDB 8.1, hedged reads are removed and this parameter has no effect. **New in version 7.0.1** **Changed in version 7.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 500 Specifies the size of the routing table cache buckets used to implement chunk grouping optimization. Must be greater than `0`. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the cache chunk bucket size to `250` on a `mongod`, issue the following command at startup: ```bash mongod --setParameter routingTableCacheChunkBucketSize=250 ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 600000 If set on the config server's primary, the interval, in milliseconds, at which the config server's primary checks the index consistency of sharded collections. The parameter has no effect on the [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) if it is not the config server's primary. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, the following sets the interval at 300000 milliseconds (5 minutes) at startup: ```javascript mongod --setParameter shardedIndexConsistencyCheckIntervalMS=300000 ``` **See also:** - [`enableShardedIndexConsistencyCheck`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.enableShardedIndexConsistencyCheck) parameter - [`shardedIndexConsistency`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.shardedIndexConsistency) metrics returned by the [`serverStatus`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-dbcommand-dbcmd.serverStatus) command. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: 300000 (5 minutes) Maximum time that [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) goes without communication to a host before [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) drops all connections to the host. If set, [`ShardingTaskExecutorPoolHostTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolHostTimeoutMS) should be greater than the sum of [`ShardingTaskExecutorPoolRefreshRequirementMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS) and [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS). Otherwise, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) adjusts the value of [`ShardingTaskExecutorPoolHostTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolHostTimeoutMS) to be greater than the sum. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolHostTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolHostTimeoutMS) to `120000` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolHostTimeoutMS=120000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolHostTimeoutMS: 120000 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: 2 Maximum number of simultaneous initiating connections (including pending connections in setup/refresh state) each TaskExecutor connection pool can have to a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. You can set this parameter to control the rate at which [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) adds connections to a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. If set, [`ShardingTaskExecutorPoolMaxConnecting`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxConnecting) should be less than or equal to [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize). If it is greater, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ignores the [`ShardingTaskExecutorPoolMaxConnecting`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxConnecting) value. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolMaxConnecting`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxConnecting) to `20` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolMaxConnecting=20 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMaxConnecting: 20 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: - On-prem deployments: `32767` for both [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) and [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) - MongoDB Atlas: - `250` for [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) routers - `32767` for [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances **Note:** While the maximum configurable value is 2 64 - 1, the defaults for both on-premises and MongoDB Atlas deployments are significantly lower to optimize performance and resource usage. Maximum number of outbound connections each TaskExecutor connection pool can open to any given [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. The maximum possible connections to any given host across all TaskExecutor pools is: ```none ShardingTaskExecutorPoolMaxSize * taskExecutorPoolSize ``` This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) to `20` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolMaxSize=20 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMaxSize: 20 } ) ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) can have up to `n` TaskExecutor connection pools, where `n` is the number of cores. See [`taskExecutorPoolSize`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.taskExecutorPoolSize) **See also:** [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) **New in version 8.2** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: Non-negative integer Default: 0 The maximum number of connection requests that an executor queues before it begins rejecting additional requests. A value of `0` means there is no limit to the size of the queue. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets `ShardingTaskExecutorPoolMaxQueueDepth` to `10` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolMaxQueueDepth=10 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMaxQueueDepth: 10 } ) ``` **New in version 6.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: -1 Optional override for [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) to set the maximum number of outbound connections each TaskExecutor connection pool can open to a [configuration server.](https://www.mongodb.com/docs/manual/core/sharded-cluster-config-servers.md#std-label-sharding-config-server) When set to: - `-1`, [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) is used. This is the default. - an integer value greater than `-1`, overrides the maximum number of outbound connections each TaskExecutor connection pool can open to a configuration server. Parameter only applies to sharded deployments. The following example sets [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) to `2` during startup, which sets the maximum number of outbound connections each TaskExecutor connection pool can open to a configuration server to `2`: This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongos --setParameter ShardingTaskExecutorPoolMaxSizeForConfigServers=2 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMaxSizeForConfigServers: 2 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: 1 Minimum number of outbound connections each TaskExecutor connection pool can open to any given [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. `ShardingTaskExecutorPoolMinSize` connections are created the first time a connection to a new host is requested from the pool. While the pool is idle, the pool maintains this number of connections until [`ShardingTaskExecutorPoolHostTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolHostTimeoutMS) milliseconds pass without any application using that pool. For a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) using the [`warmMinConnectionsInShardingTaskExecutorPoolOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartup) parameter, the `ShardingTaskExecutorPoolMinSize` parameter also controls how many connections to each shard host are established on startup of the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance before it begins accepting incoming client connections. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) to `2` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolMinSize=2 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMinSize: 2 } ) ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) can have up to `n` TaskExecutor connection pools, where `n` is the number of cores. See [`taskExecutorPoolSize`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.taskExecutorPoolSize) **See also:** - [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) - [`warmMinConnectionsInShardingTaskExecutorPoolOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartup) **New in version 6.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: -1 Optional override for [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) to set the minimum number of outbound connections each TaskExecutor connection pool can open to a [configuration server.](https://www.mongodb.com/docs/manual/core/sharded-cluster-config-servers.md#std-label-sharding-config-server) When set to: - `-1`, [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) is used. This is the default. - an integer value greater than `-1`, overrides the minimum number of outbound connections each TaskExecutor connection pool can open to a configuration server. Parameter only applies to sharded deployments. The following example sets [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) to `2` during startup, which sets the minimum number of outbound connections each TaskExecutor connection pool can open to a configuration server to `2`: This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongos --setParameter ShardingTaskExecutorPoolMinSizeForConfigServers=2 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolMinSizeForConfigServers: 2 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: 60000 (1 minute) Maximum time the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) waits before attempting to heartbeat an idle connection in the pool. An idle connection may be discarded during the refresh if the pool is above its [minimum size.](https://www.mongodb.com/docs/manual/reference/parameters.md#std-label-sharding-pool-minsize-parameters) If set, [`ShardingTaskExecutorPoolRefreshRequirementMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS) should be greater than [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS). Otherwise, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) adjusts the value of [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS) to be less than [`ShardingTaskExecutorPoolRefreshRequirementMS`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolRefreshRequirementMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS) to `90000` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolRefreshRequirementMS=90000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolRefreshRequirementMS: 90000 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: integer Default: 20000 (20 seconds) Maximum time the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) waits for a heartbeat before timing out the heartbeat. If set, [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS) should be less than [`ShardingTaskExecutorPoolRefreshRequirementMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS). Otherwise, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) adjusts the value of [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS) to be less than [`ShardingTaskExecutorPoolRefreshRequirementMS`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshRequirementMS) This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets [`ShardingTaskExecutorPoolRefreshTimeoutMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolRefreshTimeoutMS) to `30000` during startup: ```bash mongos --setParameter ShardingTaskExecutorPoolRefreshTimeoutMS=30000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolRefreshTimeoutMS: 30000 } ) ``` **Changed in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: string Default: "automatic" On a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance, this parameter sets the policy that determines the minimum size limit of its connection pools to nodes within replica sets. On a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance, this parameter sets the policy that determines the minimum size limit of its connection pools to nodes within *other* replica sets. Note that this parameter only manages connections for operations that are directly related to user requests and CRUD operations. Available values are: | Matching Policy | Description | | --- | --- | | `"automatic"` (Default) | Starting in 5.0, `"automatic"` is the new default value. When set for a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), the instance follows the behavior specified for the `"matchPrimaryNode"` option. When set for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), the instance follows the behavior specified for the `"disabled"` option. WARNING: If the [`ShardingTaskExecutorPoolReplicaSetMatching`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolReplicaSetMatching) is set to `"automatic"`, the [`replicaSetMatchingStrategy`](https://www.mongodb.com/docs/manual/reference/command/connPoolStats.md#mongodb-data-connPoolStats.replicaSetMatchingStrategy) still describes the actual policy being used, not `"automatic"`. To find the value of the [`ShardingTaskExecutorPoolReplicaSetMatching`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolReplicaSetMatching), use [`getParameter`](https://www.mongodb.com/docs/manual/reference/command/getParameter.md#mongodb-dbcommand-dbcmd.getParameter) which returns the value of the server parameter. | | `"matchPrimaryNode"` | When set for a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), the minimum size limit of the instance's connection pool to each secondary of a replica set in the sharded cluster (specifically, shard replica set and config servers) is equal to the size of its connection pool to that replica set's primary. When set for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), the minimum size limit of the instance's connection pool to each secondary of another replica set in the sharded cluster (specifically, shard replica set and config servers) is equal to the size of its connection pool to that replica set's primary. WARNING: If multiple shard servers in your topology can experience a rapid influx of cross-shard operations, do not set this option on your [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instances. In case of a primary stepdown, `matchPrimaryNode` ensures that any secondary that becomes the primary can handle the current level of primary reads and writes. | | `"matchBusiestNode"` | When set for a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), the instance's minimum size limit of the connection pool to each member of a replica set in the sharded cluster (specifically, shard replica set and config servers) is equal to the largest among the active connection counts to the primary and each secondary member of that replica set. When set for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), the instance's minimum size limit of the connection pool to each member of another replica set in the sharded cluster (specifically, shard replica set and config servers) is equal to the largest among the active connection counts to the primary and each secondary member of that replica set. With `"matchBusiestNode"`, [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) maintains enough connections to each secondary to handle the current level of primary and secondary reads and writes. The number of connections to maintain in the pool decreases as the number of active connections decreases. | | `"disabled"` | When set for a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos), the instance's minimum number of connections in the instance's connection pool to each node of a replica set in the sharded clusterv (specifically, shard replica set and config servers) is equal to the [`ShardingTaskExecutorPoolMinSize`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) When set for a [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod), the instance's minimum number of connections in the instance's connection pool to each node of another replica set in the sharded cluster (specifically, shard replica set and config servers) is equal to the [`ShardingTaskExecutorPoolMinSize`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) | This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the [`ShardingTaskExecutorPoolReplicaSetMatching`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolReplicaSetMatching) to `"automatic"` during startup: ```bash mongod --setParameter ShardingTaskExecutorPoolReplicaSetMatching="automatic" ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, ShardingTaskExecutorPoolReplicaSetMatching: "automatic" } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.3** *Type*: Integer *Default*: 1000 Maximum number of overload retry tokens allocated for each shard. Each retry attempt in response to an overload error uses a token and each attempt that succeeds frees a token. If there are no tokens available, the operation fails. For example, if `mongos` retries an operation that was previously load shed by the shard, it uses a token in the retry. If the attempt succeeds, it returns the token to the shard plus the [`shardRetryTokenReturnRate`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.shardRetryTokenReturnRate). If the attempt fails, it tries again with a new token. If it finds the bucket empty, it doesn't retry the operation. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the `shardRetryTokenBucketCapacity` to 5000 during startup: ```bash mongod --setParameter shardRetryTokenBucketCapacity=5000 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, shardRetryTokenBucketCapacity: 5000 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.3** *Type*: Double *Default*: 0.1 Return rate for shard retry tokens on successful requests. MongoDB allows the number of available retry tokens to increase over time as it processes requests. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example sets the `shardRetryTokenBucketReturnRate` to 0.25 during startup: ```bash mongod --setParameter shardRetryTokenReturnRate=0.25 ``` During run time, you can also set the parameter with the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command: ```javascript db.adminCommand( { setParameter: 1, shardRetryTokenReturnRate: 0.25 } ) ``` **New in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer *Default*: 15000 Specifies the time (in milliseconds) to wait for any ongoing database operations to complete before initiating a shutdown of [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) in response to a `SIGTERM` signal. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the time to 250 milliseconds, you can issue the following during startup: ```bash mongod --setParameter shutdownTimeoutMillisForSignaledShutdown=250 ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongod`:](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) ```javascript db.adminCommand( { setParameter: 1, shutdownTimeoutMillisForSignaledShutdown: 250 } ) ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Type: boolean Default: false When `true`, allows for starting a shard member or config server member as a standalone for maintenance operations. This parameter is mutually exclusive with the [`--configsvr`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--configsvr) or [`--shardsvr`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#std-option-mongod.--shardsvr) options. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter skipShardingConfigurationChecks=true ``` **Important:** Once maintenance has completed, remove the [`skipShardingConfigurationChecks`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.skipShardingConfigurationChecks) parameter when restarting the [`mongod`.](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) Type: integer Default: 1 The number of Task Executor connection pools to use for a given [`mongos`.](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) If the parameter value is `0` or less, the number of Task Executor connection pools is the number of cores with the following exceptions: - If the number of cores is less than 4, the number of Task Executor connection pools is 4. - If the number of cores is greater than 64, the number of Task Executor connection pools is 64. The default value of [`taskExecutorPoolSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.taskExecutorPoolSize) is `1`: This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongos --setParameter taskExecutorPoolSize=6 ``` **See also:** - [`ShardingTaskExecutorPoolMaxSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMaxSize) - [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.2** Type: boolean *Default*: true Controls whether long-running read operations on secondary nodes automatically terminate before [orphaned document](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-orphaned-document) deletion following a [chunk](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-chunk) migration. In sharded clusters, when a chunk successfully migrates from the source shard to the destination shard, MongoDB does not immediately remove the migrated documents from the source shard. Instead, the primary of the source shard waits for any in-progress reads involving the namespace of the migrated chunk to complete, and after that, waits an additional period controlled by [`orphanCleanupDelaySecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.orphanCleanupDelaySecs) (default: 1 hour). This additional delay allows any long-running secondary reads to finish before orphaned documents are deleted from the source shard. After the orphaned documents are deleted from the source shard, any ongoing reads running on secondary nodes that started before the chunk migration may silently miss documents without returning an error unless `terminateSecondaryReadsOnOrphanCleanup` is set to `true`. When `terminateSecondaryReadsOnOrphanCleanup` is set to `true`, read operations on secondary nodes that began before the chunk migration commit are automatically terminated before the orphaned documents are removed from the secondary node. This prevents long-running secondary reads from silently missing documents that were moved during migration. When set to `false`, read operations on secondary nodes continue executing even after orphaned documents are deleted. Operations may silently miss documents without returning an error. This matches the behavior in MongoDB versions before 8.2. **Note:** This behavior only affects read operations that start before the chunk migration commit. It applies to all read operations on secondaries, including queries, aggregations, and operations spanning multiple namespaces. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. #### Error Response When a read operation terminates due to `terminateSecondaryReadsOnOrphanCleanup`, MongoDB returns the following error: ```shell { code: 175, name: QueryPlanKilled, categories: [CursorInvalidatedError], errmsg: "Read has been terminated due to orphan range cleanup" } ``` This error is not retryable by design. To learn more about handling these errors, see [Long-Running Secondary Reads in Sharded Clusters.](https://www.mongodb.com/docs/manual/core/long-running-secondary-reads.md#std-label-long-running-secondary-reads) [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) Type: boolean *Default*: true Configures a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance to prewarm its connection pool on startup. With this parameter enabled, the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) attempts to establish [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) network connections to each shard server as part of its startup procedure, before it begins accepting client connections. A timeout for this behavior can be configured with the [`warmMinConnectionsInShardingTaskExecutorPoolOnStartupWaitMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartupWaitMS) parameter. If this timeout is reached, the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) will begin accepting client connections regardless of the size of its connection pool. A [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) instance with this parameter enabled may experience longer startup times, but will result in faster servicing of initial client connections once started. [`warmMinConnectionsInShardingTaskExecutorPoolOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartup) is enabled by default. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** - [`warmMinConnectionsInShardingTaskExecutorPoolOnStartupWaitMS`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartupWaitMS) - [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) Type: integer *Default*: 2000 (2 seconds) Sets the timeout threshold in milliseconds for a [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) to wait for [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) connections to be established per shard host when using the [`warmMinConnectionsInShardingTaskExecutorPoolOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartup) parameter. If this timeout is reached, the [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) will begin accepting client connections regardless of the size of its connection pool. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **See also:** - [`warmMinConnectionsInShardingTaskExecutorPoolOnStartup`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.warmMinConnectionsInShardingTaskExecutorPoolOnStartup) - [`ShardingTaskExecutorPoolMinSize`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.ShardingTaskExecutorPoolMinSize) ### Health Manager Parameters [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: Document The amount of time to wait from a [Health Managers Overview](https://www.mongodb.com/docs/manual/administration/health-managers.md#std-label-health-managers-overview) failure until the [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) is removed from the cluster, in seconds. When a failure is detected and a Health Manager is configured as `critical`, the server waits for the specified interval before removing the `mongos` from the cluster. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. For example, to set the duration from failure to crash to five minutes, issue the following at startup: ```bash mongos --setParameter activeFaultDurationSecs=300 ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ```javascript db.adminCommand( { setParameter: 1, activeFaultDurationSecs: 300 } ) ``` Parameters set with [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) do not persist across restarts. See the [setParameter page](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#std-label-setParameter-commands-not-persistent) for details. To make this setting persistent, set `activeFaultDurationSecs` in your [mongos config file](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options) using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) option as in the following example: ```yaml setParameter: activeFaultDurationSecs: 300 ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: Array of documents Use this parameter to set intensity levels for Health Managers. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. `healthMonitoringIntensities` accepts an array of documents, `values`. Each document in `values` takes two fields: - `type`, the Health Manager facet - `intensity`, the intensity level #### Health Managers | Facet | What the Health Observer Checks | | --- | --- | | `configServer` | Cluster health issues related to connectivity to the config server. | | `dns` | Cluster health issues related to DNS availability and functionality. | | `ldap` | Cluster health issues related to LDAP availability and functionality. | #### Intensity Levels | Intensity Level | Description | | --- | --- | | `critical` | The Health Manager on this facet is enabled and has the ability to move the failing [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) out of the cluster if an error occurs. The Health Manager waits the amount of time specified by [`activeFaultDurationSecs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.activeFaultDurationSecs) before stopping and moving the [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) out of the cluster automatically. | | `non-critical` | The Health Manager on this facet is enabled and logs errors, but the [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) remains in the cluster if errors are encountered. | | `off` | The Health Manager on this facet is disabled. The [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) does not perform any health checks on this facet. This is the default intensity level. | For example, to set the `dns` Health Manager facet to the `critical` intensity level, issue the following at startup: ```bash mongos --setParameter 'healthMonitoringIntensities={ values:[ { type:"dns", intensity: "critical"} ] }' ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ```javascript db.adminCommand( { setParameter: 1, healthMonitoringIntensities: { values: [ { type: "dns", intensity: "critical" } ] } } ) } ) ``` Parameters set with [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) do not persist across restarts. See the [setParameter page](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#std-label-setParameter-commands-not-persistent) for details. To make this setting persistent, set `healthMonitoringIntensities` in your [mongos config file](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options) using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) option as in the following example: ```yaml setParameter: healthMonitoringIntensities: "{ values:[ { type:\"dns\", intensity: \"critical\"} ] }" ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: Array of documents How often this Health Manager will run, in milliseconds. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. `healthMonitoringIntervals` accepts an array of documents, `values`. Each document in `values` takes two fields: - `type`, the Health Manager facet - `interval`, the time interval it runs at, in milliseconds #### Health Managers | Facet | What the Health Observer Checks | | --- | --- | | `configServer` | Cluster health issues related to connectivity to the config server. | | `dns` | Cluster health issues related to DNS availability and functionality. | | `ldap` | Cluster health issues related to LDAP availability and functionality. | For example, to set the `ldap` Health Manager facet to the run health checks every 30 seconds, issue the following at startup: ```bash mongos --setParameter 'healthMonitoringIntervals={ values:[ { type:"ldap", interval: "30000"} ] }' ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ```javascript db.adminCommand( { setParameter: 1, healthMonitoringIntervals: { values: [ { type: "ldap", interval: "30000" } ] } } ) } ) ``` Parameters set with [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) do not persist across restarts. See the [setParameter page](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#std-label-setParameter-commands-not-persistent) for details. To make this setting persistent, set `healthMonitoringIntervals` in your [mongos config file](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options) using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) option as in the following example: ```yaml setParameter: healthMonitoringIntervals: "{ values: [{type: \"ldap\", interval: 200}] }" ``` [`mongos`](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) *Type*: Document [Progress Monitor](https://www.mongodb.com/docs/manual/administration/health-managers.md#std-label-health-managers-progress-monitor) runs tests to ensure that Health Manager checks do not become stuck or unresponsive. Progress Monitor runs these tests in intervals specified by `interval`. If a health check begins but does not complete within the timeout given by `deadline`, Progress Monitor stops the [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) and removes it from the cluster. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. #### `progressMonitor` Fields | Field | Description | Units | | --- | --- | --- | | `interval` | How often to ensure Health Managers are not stuck or unresponsive. | Milliseconds | | `deadline` | Timeout before automatically failing the [mongos](https://www.mongodb.com/docs/manual/reference/program/mongos.md#std-program-mongos) if a Health Manager check is not making progress. | Seconds | To set the `interval` to 1000 milliseconds and the `deadline` to 300 seconds, issue the following at startup: ```bash mongos --setParameter 'progressMonitor={"interval": 1000, "deadline": 300}' ``` Or if using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command in a [`mongosh`](https://www.mongodb.com/docs/mongodb-shell.md#mongodb-binary-bin.mongosh) session that is connected to a running [`mongos`:](https://www.mongodb.com/docs/manual/reference/program/mongos.md#mongodb-binary-bin.mongos) ```javascript db.adminCommand( { setParameter: 1, progressMonitor: { interval: 1000, deadline: 300 } ) } ) ``` Parameters set with [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) do not persist across restarts. See the [setParameter page](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#std-label-setParameter-commands-not-persistent) for details. To make this setting persistent, set `progressMonitor` in your [mongos config file](https://www.mongodb.com/docs/manual/reference/configuration-options.md#std-label-configuration-options) using the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) option as in the following example: ```yaml setParameter: progressMonitor: "{ interval: 1000, deadline: 300 }" ``` ### Storage Parameters [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.1.0** *Type*: boolean *Default*: false Specifies whether the instance runs automatic background [compaction.](https://www.mongodb.com/docs/manual/reference/privilege-actions.md#mongodb-authaction-compact) This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. The following example enables automatic background compaction on the instance: ```bash mongod --setParameter "enableAutoCompaction=true" ``` [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `false` If [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `true`, new files created by MongoDB have permissions in accordance with the user's `umask` settings. You cannot set [`processUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.processUmask) if [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `true`. If [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `false`, new files created by MongoDB have permissions set to `600`, which gives read and write permissions only to the owner. New directories have permissions set to `700`. You can use [`processUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.processUmask) to override the default permissions for groups and other users on all new files created by MongoDB. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. ```bash mongod --setParameter honorSystemUmask=true ``` **Note:** [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is not available on Windows systems. [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Specify an integer between `1` and `500` signifying the number of milliseconds (ms) between journal commits. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Consider the following example which sets the [`journalCommitInterval`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.journalCommitInterval) to `200` ms: ```javascript db.adminCommand( { setParameter: 1, journalCommitInterval: 200 } ) ``` **See also:** [`storage.journal.commitIntervalMs`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.journal.commitIntervalMs) **New in version 5.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: `300` The minimum time window in seconds for which the storage engine keeps the snapshot history. If you query data using read concern [`"snapshot"`](https://www.mongodb.com/docs/manual/reference/read-concern-snapshot.md#mongodb-readconcern-readconcern.-snapshot-) and specify an [atClusterTime](https://www.mongodb.com/docs/manual/reference/read-concern-snapshot.md#std-label-atClusterTime) value older than the specified `minSnapshotHistoryWindowInSeconds`, [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) returns a `SnapshotTooOld` error. **Warning:** In sharded clusters, changing the default `minSnapshotHistoryWindowInSeconds` value on [config server](https://www.mongodb.com/docs/manual/core/sharded-cluster-config-servers.md#std-label-sharding-config-server) nodes may cause internal operations to fail. Do not set `minSnapshotHistoryWindowInSeconds` to `0` on config server nodes. Setting this parameter to `0` causes internal operations conducting `snapshot` reads targeting the config server with a specified `atClusterTime` to fail. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Specify an integer greater than or equal to (`>=`) 0. Consider the following example which sets the `minSnapshotHistoryWindowInSeconds` to `600` seconds: ```javascript db.adminCommand( { setParameter: 1, minSnapshotHistoryWindowInSeconds: 600 } ) ``` **Note:** Increasing the value of [`minSnapshotHistoryWindowInSeconds`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.minSnapshotHistoryWindowInSeconds) increases disk usage. For more information, see [Snapshot History Retention.](https://www.mongodb.com/docs/manual/core/wiredtiger.md#std-label-storage-snapshot-history) To modify this value for a [MongoDB Atlas](https://www.mongodb.com/docs/atlas/) cluster, you must contact [Atlas Support.](https://www.mongodb.com/docs/atlas/support/) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Overrides the default permissions used for groups and other users when [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `false`. By default, when [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `false`, new files created by MongoDB have permissions set to `600`. Use the `processUmask` parameter to override this default with a custom `umask` value. The file owner inherits permissions from the system `umask`. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. You cannot set this parameter if [`honorSystemUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.honorSystemUmask) is set to `true`. Consider the following example, which sets the permissions for groups and other users to read/write only and retains the system `umask` settings for the owner: ```bash mongod --setParameter processUmask=011 ``` **Note:** [`processUmask`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.processUmask) is not available on Windows systems. **New in version 8.3** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: The value of the [`dbPath`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.dbPath) setting. *Type*: string Path used by the spill engine when it writes to disk. You may find this useful when there is a risk of disk spill operations reducing the IOPS for concurrent queries. This parameter is only available at startup. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **Changed in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer Specifies the maximum number of concurrent read transactions (read tickets) allowed into the storage engine. **Note:** Starting in version 7.0, MongoDB dynamically adjusts the number of tickets to optimize performance, with a highest possible value of 128. Modifying this value can cause performance issues or errors. To determine if disabling the dynamic concurrent storage engine transactions algorithm is optimal for the cluster, contact [MongoDB Support.](https://www.mongodb.com/docs/manual/support/) Starting in MongoDB 7.0, this parameter is available for all storage engines. In earlier versions, this parameter is available for the WiredTiger storage engine only. **See also:** [`queues.execution`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.queues.execution) **Changed in version 7.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer Specifies the maximum number of concurrent write transactions allowed into the WiredTiger storage engine. **Note:** Starting in version 7.0, MongoDB dynamically adjusts the number of tickets to optimize performance, with a highest possible value of 128. Modifying this value can cause performance issues or errors. To determine if disabling the dynamic concurrent storage engine transactions algorithm is optimal for the cluster, contact [MongoDB Support.](https://www.mongodb.com/docs/manual/support/) Starting in MongoDB 7.0, this parameter is available for all storage engines. In earlier versions, this parameter is available for the WiredTiger storage engine only. **See also:** [`queues.execution`](https://www.mongodb.com/docs/manual/reference/command/serverStatus.md#mongodb-serverstatus-serverstatus.queues.execution) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 60 Specify the interval in seconds when [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) flushes its working memory to disk. By default, [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) flushes memory to disk every 60 seconds. In almost every situation you should not set this value and use the default setting. This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. Consider the following example which sets the `syncdelay` to `60` seconds: ```javascript db.adminCommand( { setParameter: 1, syncdelay: 60 } ) ``` To provide [durable](https://www.mongodb.com/docs/manual/reference/glossary.md#std-term-durable) data, [WiredTiger](https://www.mongodb.com/docs/manual/core/wiredtiger.md#std-label-storage-wiredtiger) uses [checkpoints](https://www.mongodb.com/docs/manual/core/wiredtiger.md#std-label-storage-wiredtiger-checkpoints). For more details, see [Journaling and the WiredTiger Storage Engine.](https://www.mongodb.com/docs/manual/core/journaling.md#std-label-journaling-wiredTiger) **See also:** - [`journalCommitInterval`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.journalCommitInterval) - [`storage.syncPeriodSecs`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-storage.syncPeriodSecs) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 1000 Specifies the initial delay before retying a write operation that was rolled back due to cache pressure. In rare circumstances, a write can fail due to cache pressure. When this happens MongoDB issues a `TemporarilyUnavailable` error and increments the `temporarilyUnavailableErrors` counter in two places: the slow query log and the [Full Time Diagnostic Data Capture (FTDC).](https://www.mongodb.com/docs/manual/administration/full-time-diagnostic-data-capture.md#std-label-ftdc-stub) Individual operations within multi-document transactions never return `TemporarilyUnavailable` errors. Adjust the write retry properties by modifying the [`temporarilyUnavailableBackoffBaseMs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableBackoffBaseMs) and [`temporarilyUnavailableMaxRetries`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableMaxRetries) parameters. [Contact support](https://www.mongodb.com/docs/atlas/support.md#std-label-request-support) if you experience any cache pressure issues. The parameter accepts: | Value | Description | | --- | --- | | `integer >= 0` | Defaults to 1 second. The initial delay between retries. The value increases with each retry to a maximum of 55 seconds. A larger value increases the chance that the cache pressure will be reduced before the next retry. To configure number of retries, use [`temporarilyUnavailableMaxRetries`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableMaxRetries) | This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. To set a new value, use [`db.adminCommand()`:](https://www.mongodb.com/docs/manual/reference/method/db.adminCommand.md#mongodb-method-db.adminCommand) ```javascript db.adminCommand( { setParameter: 1, temporarilyUnavailableBackoffBaseMs: 3 } ) ``` **New in version 6.1.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Default*: 10 Specifies the maximum number of retries when a write operation is rolled back due to cache pressure. In rare circumstances, a write can fail due to cache pressure. When this happens MongoDB issues a `TemporarilyUnavailable` error and increments the `temporarilyUnavailableErrors` counter in two places: the slow query log and the [Full Time Diagnostic Data Capture (FTDC).](https://www.mongodb.com/docs/manual/administration/full-time-diagnostic-data-capture.md#std-label-ftdc-stub) Individual operations within multi-document transactions never return `TemporarilyUnavailable` errors. Adjust the write retry properties by modifying the [`temporarilyUnavailableBackoffBaseMs`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableBackoffBaseMs) and [`temporarilyUnavailableMaxRetries`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableMaxRetries) parameters. [Contact support](https://www.mongodb.com/docs/atlas/support.md#std-label-request-support) if you experience any cache pressure issues. The parameter accepts: | Value | Description | | --- | --- | | `integer >= 0` | The maximum number of retries. There is an increasing delay between retries. To configure the backoff time, use [`temporarilyUnavailableBackoffBaseMs`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.temporarilyUnavailableBackoffBaseMs) | This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. To set a new value, use [`db.adminCommand()`:](https://www.mongodb.com/docs/manual/reference/method/db.adminCommand.md#mongodb-method-db.adminCommand) ```javascript db.adminCommand( { setParameter: 1, temporarilyUnavailableMaxRetries: 5 } ) ``` **New in version 6.1.0** [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) **New in version 8.1.0** Maximum number of retry attempts when an `upsert` operation encounters a duplicate key error. *Type*: Integer *Default*: 100 This parameter is available both at runtime and at startup: - To set the parameter at runtime, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. - To set the parameter at startup, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/configuration-options.md#mongodb-setting-setParameter) setting. **Important:** Starting in MongoDB 8.1, if an `upsert` operation runs in a multidocument transaction, then the `upsert` does not retry when it encounters a duplicate key error. The following example sets the maximum number of times the server retries an `upsert` operation when encountering a duplicate key error to `50`. ```bash mongod --setParameter "upsertMaxRetryAttemptsOnDuplicateKeyError=50" ``` During run time, you can also set the parameter with the `setParameter` command: ```javascript db.adminCommand( { setParameter: 1, upsertMaxRetryAttemptsOnDuplicateKeyError: 50 } ) ``` ### WiredTiger Parameters [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer Specifies the maximum number of concurrent read transactions (read tickets) allowed into the storage engine. **Note:** Starting in version 7.0, MongoDB dynamically adjusts the number of tickets to optimize performance, with a highest possible value of 128. Modifying this value can cause performance issues or errors. To determine if disabling the dynamic concurrent storage engine transactions algorithm is optimal for the cluster, contact [MongoDB Support.](https://www.mongodb.com/docs/manual/support/) Starting in MongoDB 7.0, this parameter is available for all storage engines. In earlier versions, this parameter is available for the WiredTiger storage engine only. **Changed in version 6.0** The `wiredTigerConcurrentReadTransactions` parameter was renamed to [`storageEngineConcurrentReadTransactions`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.storageEngineConcurrentReadTransactions) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) *Type*: integer Specifies the maximum number of concurrent write transactions allowed into the WiredTiger storage engine. **Note:** Starting in version 7.0, MongoDB dynamically adjusts the number of tickets to optimize performance, with a highest possible value of 128. Modifying this value can cause performance issues or errors. To determine if disabling the dynamic concurrent storage engine transactions algorithm is optimal for the cluster, contact [MongoDB Support.](https://www.mongodb.com/docs/manual/support/) Starting in MongoDB 7.0, this parameter is available for all storage engines. In earlier versions, this parameter is available for the WiredTiger storage engine only. **Changed in version 6.0** The `wiredTigerConcurrentWriteTransactions` parameter was renamed to [`storageEngineConcurrentWriteTransactions`.](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.storageEngineConcurrentWriteTransactions) [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) Specify `wiredTiger` storage engine configuration options for a running [`mongod`](https://www.mongodb.com/docs/manual/reference/program/mongod.md#mongodb-binary-bin.mongod) instance. This parameter is only available at runtime. To set the parameter, use the [`setParameter`](https://www.mongodb.com/docs/manual/reference/command/setParameter.md#mongodb-dbcommand-dbcmd.setParameter) command. **Warning:** Avoid modifying the [`wiredTigerEngineRuntimeConfig`](https://www.mongodb.com/docs/manual/reference/parameters.md#mongodb-parameter-param.wiredTigerEngineRuntimeConfig) unless under the direction from MongoDB engineers as this setting has major implication across both WiredTiger and MongoDB. Consider the following operation prototype: ```javascript db.adminCommand({ "setParameter": 1, "wiredTigerEngineRuntimeConfig": "