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Configure Additional Settings

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You can configure the following additional settings for your Atlas cluster.

Atlas supports creating clusters with the following tiers and MongoDB versions:

MongoDB Version
Supported on M10+
Supported on Free and Shared Tiers (M0, M2, M5)
MongoDB 4.2
MongoDB 4.4
MongoDB 5.0
MongoDB 6.0 Release Candidate
Latest Release (auto-upgrades)

MongoDB 6.0 is a release candidate, made available for early testing. To learn more, see MongoDB v6.0 Release Notes. Atlas will upgrade the cluster to the stable release version when it is generally available.

To use a rapid release MongoDB version, you must select Latest Release for auto-upgrades. You can't select a specific rapid release version.

As new patch releases become available, Atlas upgrades to these releases via a rolling process to maintain cluster availability.

To learn more about how Atlas handles end of life of major MongoDB versions, see What happens to Atlas clusters using a MongoDB version nearing end of life?.


Before you upgrade your cluster, refer to the current recommended best practices for major version upgrades.

To select the MongoDB version for your cluster, use the dropdown in the Additional Settings section of the cluster form.

You can upgrade an existing Atlas cluster to a newer major MongoDB version, if available, when you scale a cluster. However, you can't downgrade a cluster's MongoDB version.


If your project contains a custom role that uses actions introduced in a specific MongoDB version, you can't create a cluster with a MongoDB version less than that version unless you delete the custom role.

If you select Latest Release, Atlas uses the most recent MongoDB release for your cluster. Atlas also upgrades your cluster to the new major and rapid version releases via a rolling process to maintain cluster availability as each release becomes available.

You can select Latest Release only if your cluster is running the most recent major release of MongoDB.


You can upgrade your clusters to the Latest Release only if they run MongoDB 5.0.

To learn more about MongoDB versions, see MongoDB Versioning in the MongoDB Manual.

This section describes the backup configuration options for your Atlas cluster.

Atlas automatically enables backups for M2 and M5 shared clusters and you can't disable them. To learn more, see Shared Cluster Backups.

To enable backups for an M10+ Atlas cluster, toggle Turn on Backup (M10 and up) to Yes. If enabled, Atlas takes snapshots of your databases at regular intervals and retains them according to your project's retention policy.

Atlas provides the following backup options for M10+ clusters:

Backup Option
Legacy Backup Deprecated

Effective 23 March 2020, all new clusters can only use Cloud Backups.

When you upgrade to 4.2, your backup system upgrades to cloud backup if it is currently set to legacy backup. After this upgrade:

Atlas takes incremental snapshots of the data in your cluster and lets you restore the data from stored snapshots or from a selected point in time within the last 24 hours. You can also query a legacy backup snapshot.

Each project has one backup data center location dictated by the first backup-enabled cluster created in that project. To learn more, see Snapshot Storage Location.

Atlas takes incremental snapshots of the data in your cluster and lets you restore the data from those snapshots. Atlas stores snapshots in the same cloud provider region as the replica set member targeted for snapshots.

You can configure Online Archive to move infrequently accessed data from your Atlas cluster to a MongoDB-managed read-only federated database instance instead of sharding your collection or upgrading your cluster tier. To learn more about Online Archive, see Manage Online Archives.

To deploy your cluster as a sharded cluster, toggle Shard your cluster (M30 and up) to Yes.

Sharded clusters support horizontal scaling and consist of shards, config servers and mongos routers:

  • Atlas deploys each shard as a three-node replica set, where each node deploys using the configured Cloud Provider & Region, Cluster Tier, and Additional Settings. Atlas deploys one mongod per shard node.

    For cross-region clusters, the number of nodes per shard is equal to the total number of electable and read-only nodes across all configured regions. Atlas distributes the shard nodes across the selected regions.

  • Atlas deploys the config servers as a three-node replica set. The config servers run on M30 cluster tiers.

    For cross-region clusters, Atlas distributes the config server replica set nodes to ensure optimal availability. For example, Atlas might deploy the config servers across three distinct availability zones and three distinct regions if supported by the selected cloud service provider and region configuration.

  • Atlas deploys one mongos router for each node in each shard. For cross-region clusters, this allows clients using a MongoDB driver to connect to the geographically "nearest" mongos.

    To calculate the number of mongos routers in a cluster, multiply the number of shards by the number of replica set nodes per shard.

You cannot convert a sharded cluster deployment to a replica set deployment.

To learn more about how the number of server instances affect cost, see Number of Nodes.

To learn more about sharded clusters, see Sharding in the MongoDB manual.

This field is visible only if the deployment is a sharded cluster.

You can set the number of shards to deploy with the sharded cluster. Your cluster can have between 1 and 50 shards, inclusive.


When you remove a shard, Atlas uses the movePrimary command to move any unsharded databases in that shard to a remaining shard.

All sharded collections remain online and available during the shard removal process. However, read or write operations to unsharded collections during the movePrimary operation can result in unexpected behavior, including migration failure or data loss.

We recommend moving the primary shard for any databases containing unsharded collections before removing the shard.

For more information, see Remove Shards from an Existing Sharded Cluster.

Don't create a sharded cluster with a single shard for production environments. Single-shard sharded clusters don't provide the same benefits as multi-shard configurations.

If your cluster tier is M30 or higher, you can upgrade your replica set deployment to a sharded cluster deployment.

Once the upgrade completes, you must restart all application clients and reconnect to your sharded cluster. If you don't restart the application clients, your data might be inconsistent once Atlas begins distributing data across shards.

  • If you are using a DNS Seed List connection string, your application automatically connects to the mongos for your sharded cluster.
  • If you are using a standard connection string, you must update your connection string to reflect your new cluster topology.

To enable BI Connector for Atlas for this cluster, toggle Enable Business Intelligence Connector (M10 and up) to Yes.


The MongoDB Connector for Business Intelligence for Atlas (BI Connector) is only available for M10 and larger clusters.

The BI Connector is a powerful tool which provides users SQL-based access to their MongoDB databases. As a result, the BI Connector performs operations which may be CPU and memory intensive. Given the limited hardware resources on M10 and M20 cluster tiers, you may experience performance degradation of the cluster when enabling the BI Connector. If this occurs, upgrade to an M30 or larger cluster or disable the BI Connector.

If enabled, select the node type from which BI Connector for Atlas should read.

The following table describes the available read preferences for BI Connector and their corresponding readPreference and readPreferenceTag connection string options.

BI Connector Read Preference
Read from the primary node.
Read from secondary nodes.
{ nodeType : ELECTABLE } or { nodeType : READ_ONLY }
Read from analytics nodes.
{ nodeType : ANALYTICS }

The nodeType read preference tag dictates the type of node BI Connector for Atlas connects to. You can specify the following values for this option:

  • ELECTABLE restricts BI Connector to the primary and electable secondary nodes.
  • READ_ONLY restricts BI Connector to connecting to non-electable secondary nodes.
  • ANALYTICS restricts BI Connector to connecting to analytics nodes.


    When you use the Analytics read preference, Atlas places BI Connector for Atlas on the same hardware as the analytics nodes that BI Connector for Atlas reads from.

    By isolating electable data-bearing nodes from the BI Connector for Atlas, electable nodes don't compete for resources with BI Connector for Atlas, thus improving cluster reliability and performance.

For high traffic production environments, connecting to the Secondary Node(s) or Analytics Node(s) may be preferable to connecting to the Primary Node.

For clusters with one or more analytics nodes, select Analytics Node to isolate BI Connector for Atlas queries from your operational workload and read from dedicated, read-only analytics nodes. With this option, electable nodes don't compete for resources with BI Connector for Atlas, thus improving cluster reliability and performance.

The BI Connector generates a relational schema by sampling data from MongoDB. You can configure the following sampling settings:

BI Connector Option
Schema Sample Size
Optional. The number of documents that the BI Connector samples for each database when it gathers schema information. To learn more, see the BI Connector documentation.
Sample Refresh Interval
Optional. The frequency, in seconds, at which the BI Connector re-samples data to recreate the schema.To learn more, see the BI Connector documentation.
Feature unavailable in Free and Shared-Tier Clusters

This feature is not available for M0 free clusters, M2, and M5 clusters. To learn more about which features are unavailable, see Atlas M0 (Free Cluster), M2, and M5 Limitations.

Atlas encrypts all cluster storage and snapshot volumes, ensuring the security of all cluster data at rest (Encryption at Rest). Atlas Project Owners can configure an added layer of encryption on their data at rest using the MongoDB Encrypted Storage Engine and their Atlas-compatible Encryption at Rest provider.

Atlas supports the following Encryption at Rest providers:

To start managing your own encryption keys for this cluster, toggle Encryption using your Key Management (M10 and up) to Yes.

Atlas Encryption at Rest using your Key Management is available for M10+ replica set clusters. Atlas Encryption at Rest supports encrypting Back Up Your Database Deployment only. You can't enable Encryption at Rest on a cluster using Legacy Backups (Deprecated).

Managing your own encryption keys incurs an increase to the hourly run costs of your clusters. To learn more about Atlas billing for advanced security features, see Advanced Security.


If Atlas can't access the Atlas project key management provider or the encryption key used to encrypt a cluster, that cluster becomes inaccessible and unrecoverable. Exercise extreme caution before you modify, delete, or disable an encryption key or the key management provider credentials that Atlas uses.

You can configure the following mongod runtime options on M10+ paid tier clusters.

Atlas dynamically modifies the Oplog Size for replica sets and sharded clusters. However, for the Minimum TLS Protocol Version and Allow Server-Side JavaScript settings, it performs a rolling restart of the shard members and the config server replica set. To learn more about how Atlas supports high availability during maintenance operations, see How does MongoDB Atlas deliver high availability?.

To view these settings, open the More Configuration Options under Additional Settings in the cluster form.

Modify the oplog size of the cluster.

For sharded cluster deployments, this option modifies the oplog size of each shard in the cluster.

This option corresponds to modifying the replication.oplogSizeMB configuration file option for each mongod in the cluster.

Specify your desired Oplog Size in megabytes in the input box.


Reducing the size of the oplog requires removing data from the oplog. Atlas can't access or restore any oplog entries removed as a result of oplog reduction. Consider the ramifications of this data loss before you reduce the oplog.

  • You can't set the oplog to less than 990 megabytes.
  • Atlas places no upper limit in megabytes on the oplog. However, Atlas returns an error if the oplog size you choose leaves your cluster's disk with less than 25 percent of its capacity free.

To check the oplog size:

  1. Connect to your cluster via mongosh.
  2. Authenticate as a user with the Atlas admin role.
  3. Run the rs.printReplicationInfo() method.

Atlas displays the current oplog size and time.

Don't reduce the size of the oplog to increase the available disk space. Only the oplog collection ( can reclaim the space that reducing the oplog size saves. Other collections don't benefit from reducing oplog storage.

Enable or disable enforcement of the 1024-byte index key limit. Documents can only be updated or inserted if, for all indexed fields on the target collection, the corresponding index entries don't exceed 1024 bytes.

If disabled, mongod writes documents that breach the limit but doesn't index them. This option corresponds to modifying the failIndexKeyTooLong parameter via the setParameter command for each mongod in the cluster.

Index Key Limit

failIndexKeyTooLong was deprecated in MongoDB version 4.2 and is removed in MongoDB 4.4 and later. For MongoDB prior to 4.2, set this parameter to false.

Enable or disable execution of operations that perform server-side execution of JavaScript.

  • If your cluster runs a MongoDB version less than 4.4, this option corresponds to modifying the security.javascriptEnabled configuration file option for each mongod in the cluster.
  • If your cluster runs MongoDB version 4.4 or greater, this option corresponds to modifying the security.javascriptEnabled configuration file option for each mongod and mongos in the cluster.

In MongoDB version 4.4 and later, security.javascriptEnabled applies to mongos' as well.

Set the minimum TLS version that the cluster accepts for incoming connections. This option corresponds to configuring the net.ssl.disabledProtocols configuration file option for each mongod in the cluster.

TLS 1.0 Deprecation

If you are considering this option as a method for enabling the deprecated Transport Layer Security (TLS) 1.0 protocol version, read What versions of TLS does Atlas support? before proceeding. Atlas deprecation of TLS 1.0 improves your security of data-in-transit and aligns with industry best practices. Enabling TLS 1.0 for any Atlas cluster carries security risks. Consider enabling TLS 1.0 only for as long as required to update your application stack to support TLS 1.1 or later.

Enable or disable the execution of queries that require a collection scan to return results. This option corresponds to modifying the notablescan parameter via the setParameter command for each mongod in the cluster.

Set the default level of acknowledgment requested from MongoDB for read operations for this cluster.


You can set the default read concern only for Atlas clusters that run MongoDB 4.4 or higher.

MongoDB 4.4 clusters default to available.

Starting with MongoDB 5.0, the default read concern for clusters is local.

Set the default level of acknowledgment requested from MongoDB for write operations for this cluster.


You can set the default write concern only for Atlas clusters that run MongoDB 4.4 or higher.

MongoDB 4.4 clusters default to 1.

Starting with MongoDB 5.0, the default write concern for clusters is majority.

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