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mongodump

macOS Sierra and Go 1.6 Incompatibility

Users running on macOS Sierra require the 3.2.10 or newer version of mongodump.

Synopsis

mongodump is a utility for creating a binary export of the contents of a database. mongodump can export data from either mongod or mongos instances.

mongodump can be a part of a backup strategy with mongorestore for partial backups based on a query, syncing from production to staging or development environments, or changing the storage engine of a standalone. However, the use of mongodump and mongorestore as a backup strategy can be problematic for sharded clusters and replica sets.

Run mongodump from the system command line, not the mongo shell.

For an overview of mongodump in conjunction with mongorestore part of a backup and recovery strategy, see Back Up and Restore with MongoDB Tools.

See also

mongorestore, Back Up a Sharded Cluster with Database Dumps and MongoDB Backup Methods.

Note

If you are archiving stale data to save on storage costs, consider Online Archive in MongoDB Atlas. Online Archive automatically archives infrequently accessed data to fully-managed S3 buckets for cost-effective data tiering.

Behavior

Data Exclusion

mongodump excludes the content of the local database in its output.

mongodump only captures the documents in the database in its backup data and does not include index data. mongorestore or mongod must then rebuild the indexes after restoring data.

Changed in version 3.4: MongoDB 3.4 added support for read-only views. By default, mongodump only captures a view’s metadata: it does not create a binary export of the documents included in the view. To capture the documents in a view use --viewsAsCollections.

Read Preference

Replica Sets

Changed in version 3.2.0: The choice of target or targets for the --host parameter affects the read preference of mongodump when connecting to a replica set.

• If the string passed to --host is prefixed by the replica set name, mongodump reads from the primary replica set member by default. For example:

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  --host "replSet/rep1.example.net:27017,rep2.example.net:27017,rep3.example.net:27017"
  

• If the string passed to --host contains a list of mongod instances, but does not include the replica set name as a prefix to the host string, mongodump reads from the nearest node by default. For example:

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  --host "rep1.example.net:27017,rep2.example.net:27017,rep3.example.net:27017"
  

Sharded Clusters

Changed in version 3.0.5: For a sharded cluster where the shards are replica sets, mongodump no longer prefers reads from secondary members when run against the mongos instance.

For sharded clusters, specify the hostname of a mongos for the --host option. mongodump reads from the primary replica set member on each shard replica set in the cluster.

Unsharded collections in a sharded cluster are stored on a primary shard. mongodump reads from the primary replica set member on the primary shard for any unsharded collections. Note: each database has its own primary shard.

Overwrite Files

mongodump overwrites output files if they exist in the backup data folder. Before running the mongodump command multiple times, either ensure that you no longer need the files in the output folder (the default is the dump/ folder) or rename the folders or files.

Data Compression Handling

When run against a mongod instance that uses the WiredTiger storage engine, mongodump outputs uncompressed data.

Working Set

mongodump can adversely affect performance of the mongod. If your data is larger than system memory, the mongodump will push the working set out of memory.

Required Access

To run mongodump against a MongoDB deployment that has access control enabled, you must have privileges that grant find action for each database to back up. The built-in backup role provides the required privileges to perform backup of any and all databases.

Changed in version 3.2.1: The backup role provides additional privileges to back up the system.profile collection that exists when running with database profiling. Previously, users required read access on this collection.

Options

Changed in version 3.0.0: mongodump removed the --dbpath as well as related --directoryperdb and --journal options. To use mongodump, you must run mongodump against a running mongod or mongos instance as appropriate.

mongodump

--help

Returns information on the options and use of mongodump.

--verbose, -v

Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)

--quiet

Runs mongodump in a quiet mode that attempts to limit the amount of output.

This option suppresses:

• output from database commands
• replication activity
• connection accepted events
• connection closed events

--version

Returns the mongodump release number.

--uri <connectionString>

New in version 3.4.6.

Specify a resolvable URI connection string to connect to the MongoDB deployment.

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--uri "mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]]"

For more information on the components of the connection string, see the Connection String URI Format documentation.

Important

The following command-line options cannot be used in conjunction with --uri option:

• --host
• --port
• --db
• --username
• --password (if the URI connection string also includes the password)
• --authenticationDatabase
• --authenticationMechanism

Instead, specify these options as part of your --uri connection string.

--host <hostname><:port>, -h <hostname><:port>

Default: localhost:27017

Specifies a resolvable hostname for the mongod to which to connect. By default, the mongodump attempts to connect to a MongoDB instance running on the localhost on port number 27017.

To connect to a replica set, specify the replSetName and a seed list of set members, as in the following:

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--host <replSetName>/<hostname1><:port>,<hostname2><:port>,<...>

When specifying the replica set list format, mongodump always connects to the primary.

You can also connect to any single member of the replica set by specifying the host and port of only that member:

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--host <hostname1><:port>

Changed in version 3.0.0: If you use IPv6 and use the <address>:<port> format, you must enclose the portion of an address and port combination in brackets (e.g. [<address>]).

Note

You cannot specify both --host and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--port <port>

Default: 27017

Specifies the TCP port on which the MongoDB instance listens for client connections.

Note

You cannot specify both --port and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--ipv6

Removed in version 3.0.

Enables IPv6 support and allows mongodump to connect to the MongoDB instance using an IPv6 network. Prior to MongoDB 3.0, you had to specify --ipv6 to use IPv6. In MongoDB 3.0 and later, IPv6 is always enabled.

--ssl

New in version 2.6.

Enables connection to a mongod or mongos that has TLS/SSL support enabled.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslCAFile <filename>

New in version 2.6.

Specifies the .pem file that contains the root certificate chain from the Certificate Authority. Specify the file name of the .pem file using relative or absolute paths.

Starting in version 3.4, if --sslCAFile or ssl.CAFile is not specified and you are not using x.509 authentication, the system-wide CA certificate store will be used when connecting to an TLS/SSL-enabled server.

If using x.509 authentication, --sslCAFile or ssl.CAFile must be specified unless using --sslCertificateSelector.

Warning

Version 3.2 and earlier: For TLS/SSL connections (--ssl) to mongod and mongos, if the mongodump runs without the --sslCAFile, mongodump will not attempt to validate the server certificates. This creates a vulnerability to expired mongod and mongos certificates as well as to foreign processes posing as valid mongod or mongos instances. Ensure that you always specify the CA file to validate the server certificates in cases where intrusion is a possibility.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslPEMKeyFile <filename>

New in version 2.6.

Specifies the .pem file that contains both the TLS/SSL certificate and key. Specify the file name of the .pem file using relative or absolute paths.

This option is required when using the --ssl option to connect to a mongod or mongos that has CAFile enabled without allowConnectionsWithoutCertificates.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslPEMKeyPassword <value>

New in version 2.6.

Specifies the password to de-crypt the certificate-key file (i.e. --sslPEMKeyFile). Use the --sslPEMKeyPassword option only if the certificate-key file is encrypted. In all cases, the mongodump will redact the password from all logging and reporting output.

If the private key in the PEM file is encrypted and you do not specify the --sslPEMKeyPassword option, the mongodump will prompt for a passphrase. See TLS/SSL Certificate Passphrase.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslCRLFile <filename>

New in version 2.6.

Specifies the .pem file that contains the Certificate Revocation List. Specify the file name of the .pem file using relative or absolute paths.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslAllowInvalidCertificates

New in version 2.6.

Bypasses the validation checks for server certificates and allows the use of invalid certificates. When using the allowInvalidCertificates setting, MongoDB logs as a warning the use of the invalid certificate.

Starting in MongoDB 4.0, if you specify --sslAllowInvalidCertificates or ssl.allowInvalidCertificates: true when using x.509 authentication, an invalid certificate is only sufficient to establish a TLS/SSL connection but is insufficient for authentication.

Warning

Although available, avoid using the --sslAllowInvalidCertificates option if possible. If the use of --sslAllowInvalidCertificates is necessary, only use the option on systems where intrusion is not possible.

If the mongo shell (and other MongoDB Tools) runs with the --sslAllowInvalidCertificates option, the mongo shell (and other MongoDB Tools) will not attempt to validate the server certificates. This creates a vulnerability to expired mongod and mongos certificates as well as to foreign processes posing as valid mongod or mongos instances. If you only need to disable the validation of the hostname in the TLS/SSL certificates, see --sslAllowInvalidHostnames.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslAllowInvalidHostnames

New in version 3.0.

Disables the validation of the hostnames in TLS/SSL certificates. Allows mongodump to connect to MongoDB instances even if the hostname in their certificates do not match the specified hostname.

For more information about TLS/SSL and MongoDB, see Configure mongod and mongos for TLS/SSL and TLS/SSL Configuration for Clients .

--sslFIPSMode

New in version 2.6.

Directs the mongodump to use the FIPS mode of the TLS/SSL library. Your system must have a FIPS compliant library to use the --sslFIPSMode option.

Note

FIPS-compatible TLS/SSL is available only in MongoDB Enterprise. See Configure MongoDB for FIPS for more information.

--username <username>, -u <username>

Specifies a username with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --password and --authenticationDatabase options.

Note

You cannot specify both --username and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--password <password>, -p <password>

Specifies a password with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --username and --authenticationDatabase options.

Changed in version 3.0.2: To prompt the user for the password, pass the --username option without --password or specify an empty string as the --password value, as in --password "" .

Note

You cannot specify both --password and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--authenticationDatabase <dbname>

Specifies the authentication database where the specified --username has been created. See Authentication Database.

Note

You cannot specify both --authenticationDatabase and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

If you do not specify an authentication database, mongodump assumes that the database specified to export holds the user’s credentials.

If you do not specify an authentication database or a database to export, mongodump assumes the admin database holds the user’s credentials.

--authenticationMechanism <name>

Default: SCRAM-SHA-1

Specifies the authentication mechanism the mongodump instance uses to authenticate to the mongod or mongos.

Changed in version 4.0: MongoDB removes support for the deprecated MongoDB Challenge-Response (MONGODB-CR) authentication mechanism.

MongoDB adds support for SCRAM mechanism using the SHA-256 hash function (SCRAM-SHA-256).

Value	Description
SCRAM-SHA-1	RFC 5802 standard Salted Challenge Response Authentication Mechanism using the SHA-1 hash function.
SCRAM-SHA-256	RFC 7677 standard Salted Challenge Response Authentication Mechanism using the SHA-256 hash function. Requires featureCompatibilityVersion set to 4.0. New in version 4.0.
MONGODB-X509	MongoDB TLS/SSL certificate authentication.
GSSAPI (Kerberos)	External authentication using Kerberos. This mechanism is available only in MongoDB Enterprise.
PLAIN (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.

Note

You cannot specify both --authenticationMechanism and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--gssapiServiceName

New in version 2.6.

Specify the name of the service using GSSAPI/Kerberos. Only required if the service does not use the default name of mongodb.

This option is available only in MongoDB Enterprise.

--gssapiHostName

New in version 2.6.

Specify the hostname of a service using GSSAPI/Kerberos. Only required if the hostname of a machine does not match the hostname resolved by DNS.

This option is available only in MongoDB Enterprise.

--db <database>, -d <database>

Specifies a database to backup. If you do not specify a database, mongodump copies all databases in this instance into the dump files.

Note

You cannot specify both --db and --uri.

Connections to MongoDB Atlas that use the +srv connection string option require the --uri option.

--collection <collection>, -c <collection>

Specifies a collection to backup. If you do not specify a collection, this option copies all collections in the specified database or instance to the dump files.

--query <json>, -q <json>

Provides a JSON document as a query that optionally limits the documents included in the output of mongodump.

You must enclose the query document in single quotes ('{ ... }') to ensure that it does not interact with your shell environment.

--queryFile <path>

New in version 3.2.

Specifies the path to a file containing a JSON document as a query filter that limits the documents included in the output of mongodump. --queryFile enables you to create query filters that are too large to fit in your terminal’s buffer.

--readPreference <string>

Specify the read preference for mongodump.

See Read Preference Modes.

mongodump defaults to primary read preference when connected to a mongos or a replica set.

Otherwise, mongodump defaults to nearest.

Warning

Using a read preference other than primary with a connection to a mongos may produce inconsistencies, duplicates, or result in missed documents.

See Read Preference.

--forceTableScan

By default, mongodump uses the _id index when scanning collections with that index is available (e.g. 3.4-reference-views do not have any indexes). Specify --forceTableScan to direct mongodump to scan collection data without the use of the _id index.

--forceTableScan does not ensure a point-in-time snapshot. Use --oplog to create a point-in-time snapshot.

You cannot use --forceTableScan with the --query option.

MMAPv1 Only

Running mongodump with --forceTableScan against the deprecated MMAPv1 storage engine may result in multiple versions of the same document in the output.

--gzip

New in version 3.2.

Compresses the output. If mongodump outputs to the dump directory, the new feature compresses the individual files. The files have the suffix .gz.

If mongodump outputs to an archive file or the standard out stream, the new feature compresses the archive file or the data output to the stream.

--out <path>, -o <path>

Specifies the directory where mongodump will write BSON files for the dumped databases. By default, mongodump saves output files in a directory named dump in the current working directory.

To send the database dump to standard output, specify “-” instead of a path. Write to standard output if you want process the output before saving it, such as to use gzip to compress the dump. When writing standard output, mongodump does not write the metadata that writes in a <dbname>.metadata.json file when writing to files directly.

You cannot use the --archive option with the --out option.

--archive <file or null>

New in version 3.2.

Writes the output to a single archive file or to the standard output (stdout).

To output the dump to an archive file, run mongodump with the new --archive option and the archive filename.

To output the dump to the standard output stream in order to pipe to another process, run mongodump with the archive option but omit the filename.

You cannot use the --archive option with the --out option.

--repair

Note

When repairing a database, you should use mongod --repair rather than this option. For instructions on repairing a database, refer to Recover a Standalone after an Unexpected Shutdown.

Changes the behavior of mongodump to only write valid data and exclude data that may be in an invalid state as a result of an improper shutdown or mongod crash.

--repair is different from mongod --repair, and may produce a large amount of duplicate documents. It is only available for use against mongod instances using the mmapv1 storage engine. You cannot run --repair against mongos, or against mongod instances that use the wiredTiger storage engine.

For instructions on repairing a database, refer to Recover a Standalone after an Unexpected Shutdown.

--oplog

Creates a file named oplog.bson as part of the mongodump output. The oplog.bson file, located in the top level of the output directory, contains oplog entries that occur during the mongodump operation. This file provides an effective point-in-time snapshot of the state of a mongod instance. To restore to a specific point-in-time backup, use the output created with this option in conjunction with mongorestore --oplogReplay.

Without --oplog, if there are write operations during the dump operation, the dump will not reflect a single moment in time. Changes made to the database during the update process can affect the output of the backup.

Important

A mongodump running with --oplog fails if a client issues any of the listed operations during the dump process.

• renameCollection
• db.collection.renameCollection()
• db.collection.aggregate() with $out

--oplog has no effect when running mongodump against a mongos instance to dump the entire contents of a sharded cluster. However, you can use --oplog to dump individual shards.

--oplog only works against nodes that maintain an oplog. This includes all members of a replica set.

--oplog does not dump the oplog collection.

Note

To use mongodump with --oplog, you must create a full dump of a replica set member. mongodump with --oplog fails if you use any of the following options to limit the data to be dumped:

• --db
• --collection

See also

mongorestore --oplogReplay

--dumpDbUsersAndRoles

Includes user and role definitions in the database’s dump directory when performing mongodump on a specific database. This option applies only when you specify a database in the --db option. MongoDB always includes user and role definitions when mongodump applies to an entire instance and not just a specific database.

--excludeCollection string

New in version 3.0.

Excludes the specified collection from the mongodump output. To exclude multiple collections, specify the --excludeCollection multiple times.

--excludeCollectionsWithPrefix string

New in version 3.0.

Excludes all collections with a specified prefix from the mongodump outputs. To specify multiple prefixes, specify the --excludeCollectionsWithPrefix multiple times.

--numParallelCollections int, -j int

Default: 4

Number of collections mongodump should export in parallel.

--viewsAsCollections

New in version 3.4.

When specified, mongodump exports read-only views as collections. For each view, mongodump will produce a BSON file containing the documents in the view. If you mongorestore the produced BSON file, the view will be restored as a collection.

If you do not include --viewsAsCollections, mongodump captures each view’s metadata. If you include a view’s metadata file in a mongorestore operation, the view is recreated.

Examples

mongodump a Collection

The following operation creates a dump file that contains only the collection named collection in the database named test. In this case the database is running on the local interface on port 27017:

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mongodump  --db test --collection collection

mongodump a Database Excluding Specified Collections

The following operation dumps all collections in the test database except for users and salaries:

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mongodump  --db test --excludeCollection=users --excludeCollection=salaries

mongodump with Access Control

In the next example, mongodump creates a database dump located at /opt/backup/mongodump-2011-10-24, from a database running on port 37017 on the host mongodb1.example.net and authenticating using the username user and the password pass, as follows:

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mongodump --host mongodb1.example.net --port 37017 --username user --password "pass" --out /opt/backup/mongodump-2011-10-24

Output to an Archive File

New in version 3.2.

To output the dump to an archive file, run mongodump with the --archive option and the archive filename. For example, the following operation creates a file test.20150715.archive that contains the dump of the test database.

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mongodump --archive=test.20150715.archive --db test

Output an Archive to Standard Output

New in version 3.2.

To output the archive to the standard output stream in order to pipe to another process, run mongodump with the archive option but omit the filename:

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mongodump --archive --db test --port 27017 | mongorestore --archive --port 27018

Note

You cannot use the --archive option with the --out option.

Compress the Output

To compress the files in the output dump directory, run mongodump with the new --gzip option. For example, the following operation outputs compressed files into the default dump directory.

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mongodump --gzip --db test

To compress the archive file output by mongodump, use the --gzip option in conjunction with the --archive option, specifying the name of the compressed file.

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mongodump --archive=test.20150715.gz --gzip --db=test

Copy/Clone a Database

MongoDB 4.0 deprecates the copydb and the clone commands and their mongo shell helpers db.copyDatabase() and db.cloneDatabase().

As an alternative, users can use mongodump and mongorestore (with the mongorestore options --nsFrom and --nsTo).

For example, to copy the test database from a local instance running on the default port 27017 to the examples database on the same instance, you can:

1. Use mongodump to dump the test database to an archive mongodump-test-db:

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   mongodump --archive="mongodump-test-db" --db=test
   

2. Use mongorestore with --nsFrom and --nsTo to restore (with database name change) from the archive:

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   mongorestore --archive="mongodump-test-db" --nsFrom='test.*' --nsTo='examples.*'
   

Tip

Include additional options as necessary, such as to specify the uri or host, username, password and authentication database.

Alternatively, instead of using an archive file, you can mongodump the test database to the standard output stream and pipe into mongorestore:

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mongodump --archive --db=test | mongorestore --archive  --nsFrom='test.*' --nsTo='examples.*'

←   mongos.exe mongorestore  →

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