Mongodb
mongodump is a utility for creating a binary export of the contents of a database. Consider using this utility as part an effective backup strategy. Use in conjunction with mongorestore to provide restore functionality.
The format of data created by mongodump tool from the 2.2 distribution or later is different and incompatible with earlier versions of mongod.
"mongorestore" and "/administration/backups".
mongodump
--help
Returns a basic help and usage text.
--verbose, -v
Increases the amount of internal reporting returned on the command line. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)
--version
Returns the version of the mongodump utility and exits.
--host <hostname><:port>
Specifies a resolvable hostname for the mongod that you wish to use to create the database dump. By default mongodump will attempt to connect to a MongoDB process ruining on the localhost port number 27017.
Optionally, specify a port number to connect a MongoDB instance running on a port other than 27017.
To connect to a replica set, use the --host argument with a setname, followed by a slash and a comma-separated list of host names and port numbers. The mongodump utility will, given the seed of at least one connected set member, connect to the primary member of that set. This option would resemble:
mongodump --host repl0/mongo0.example.net,mongo0.example.net:27018,mongo1.example.net,mongo2.example.net
You can always connect directly to a single MongoDB instance by specifying the host and port number directly.
--port <port>
Specifies the port number, if the MongoDB instance is not running on the standard port. (i.e. 27017) You may also specify a port number using the --host option.
--ipv6
Enables IPv6 support that allows mongodump to connect to the MongoDB instance using an IPv6 network. All MongoDB programs and processes, including mongodump, disable IPv6 support by default.
--ssl
New in version 2.4: MongoDB added support for SSL connections to mongod instances in mongodump.
SSL support in mongodump is not compiled into the default distribution of MongoDB. See /administration/ssl for more information on SSL and MongoDB.
Additionally, mongodump does not support connections to mongod instances that require client certificate validation.
Allows mongodump to connect to mongod instance over an SSL connection.
--username <username>, -u <username>
Specifies a username to authenticate to the MongoDB instance, if your database requires authentication. Use in conjunction with the --password option to supply a password.
--password <password>, -p <password>
Specifies a password to authenticate to the MongoDB instance. Use in conjunction with the --username option to supply a username.
If you specify a --username without the --password option, mongodump will prompt for a password interactively.
--authenticationDatabase <dbname>
New in version 2.4.
Specifies the database that holds the user's (e.g --username) credentials.
By default, mongodump assumes that the database specified to the --db argument holds the user's credentials, unless you specify --authenticationDatabase.
See userSource, /reference/privilege-documents and /reference/user-privileges for more information about delegated authentication in MongoDB.
--authenticationMechanism <name>
New in version 2.4.
Specifies the authentication mechanism. By default, the authentication mechanism is MONGODB-CR, which is the MongoDB challenge/response authentication mechanism. In the MongoDB Subscriber Edition, mongodump also includes support for GSSAPI to handle Kerberos authentication.
See /tutorial/control-access-to-mongodb-with-kerberos-authentication for more information about Kerberos authentication.
--dbpath <path>
Specifies the directory of the MongoDB data files. If used, the --dbpath option enables mongodump to attach directly to local data files and copy the data without the mongod. To run with --dbpath, mongodump needs to restrict access to the data directory: as a result, no mongod can access the same path while the process runs.
--directoryperdb
Use the --directoryperdb in conjunction with the corresponding option to mongod. This option allows mongodump to read data files organized with each database located in a distinct directory. This option is only relevant when specifying the --dbpath option.
--journal
Allows mongodump operations to use the durability journal to ensure that the export is in a consistent state. This option is only relevant when specifying the --dbpath option.
--db <db>, -d <db>
Use the --db option to specify a database for mongodump to backup. If you do not specify a DB, mongodump copies all databases in this instance into the dump files. Use this option to backup or copy a smaller subset of your data.
--collection <collection>, -c <collection>
Use the --collection option to specify a collection for mongodump to backup. If you do not specify a collection, this option copies all collections in the specified database or instance to the dump files. Use this option to backup or copy a smaller subset of your data.
--out <path>, -o <path>
Specifies a path where mongodump and store the output the database dump. To output the database dump to standard output, specify a - rather than a path.
--query <json>, -q <json>
Provides a query to limit (optionally) the documents included in the output of mongodump.
--oplog
Use this option to ensure that mongodump creates a dump of the database that includes an oplog, to create a 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.
--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 a oplog. This includes all members of a replica set, as well as master nodes in master/slave replication deployments.
--repair
Use this option to run a repair option in addition to dumping the database. The repair option attempts to repair a database that may be in an inconsistent state as a result of an improper shutdown or mongod crash.
--forceTableScan
Forces mongodump to scan the data store directly: typically, mongodump saves entries as they appear in the index of the _id field. Use --forceTableScan to skip the index and scan the data directly. Typically there are two cases where this behavior is preferable to the default:
If you have key sizes over 800 bytes that would not be present in the _id index.
Your database uses a custom _id field.
When you run with --forceTableScan, mongodump does not use $snapshot. As a result, the dump produced by mongodump can reflect the state of the database at many different points in time.
Use --forceTableScan with extreme caution and consideration.
Changed in version 2.2: When used in combination with fsync or db.fsyncLock(), mongod may block some reads, including those from mongodump, when queued write operation waits behind the fsync lock.
When running mongodump against a mongos instance where the sharded cluster consists of replica sets, the read preference of the operation will prefer reads from secondary members of the set.
See the /tutorial/backup-databases-with-binary-database-dumps for a larger overview of mongodump usage. Also see the "mongorestore" document for an overview of the mongorestore, which provides the related inverse functionality.
The following command, 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:
mongodump --collection collection --db test
In the next example, mongodump creates a backup of the database instance stored in the /srv/mongodb directory on the local machine. This requires that no mongod instance is using the /srv/mongodb directory.
mongodump --dbpath /srv/mongodb
In the final 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:
mongodump --host mongodb1.example.net --port 37017 --username user --password pass /opt/backup/mongodump-2011-10-24
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