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Backup a Small Sharded Cluster with mongodump

Overview

If your sharded cluster holds a small data set, you can connect to a mongos using mongodump. You can create backups of your MongoDB cluster, if your backup infrastructure can capture the entire backup in a reasonable amount of time and if you have a storage system that can hold the complete MongoDB data set.

See MongoDB Backup Methods and Backup and Restore Sharded Clusters for complete information on backups in MongoDB and backups of sharded clusters in particular.

Important

By default mongodump issue its queries to the non-primary nodes.

Considerations

If you use mongodump without specifying a database or collection, mongodump will capture collection data and the cluster meta-data from the config servers.

You cannot use the --oplog option for mongodump when capturing data from mongos. As a result, if you need to capture a backup that reflects a single moment in time, you must stop all writes to the cluster for the duration of the backup operation.

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 3.0.9: The backup role provides additional privileges to back up the system.profile collections that exist when running with database profiling. Previously, users required an additional read access on this collection.

Procedure

Capture Data

You can perform a backup of a sharded cluster by connecting mongodump to a mongos. Use the following operation at your system’s prompt:

mongodump --host mongos3.example.net --port 27017

mongodump will write BSON files that hold a copy of data stored in the sharded cluster accessible via the mongos listening on port 27017 of the mongos3.example.net host.

Restore Data

Backups created with mongodump do not reflect the chunks or the distribution of data in the sharded collection or collections. Like all mongodump output, these backups contain separate directories for each database and BSON files for each collection in that database.

You can restore mongodump output to any MongoDB instance, including a standalone, a replica set, or a new sharded cluster. When restoring data to sharded cluster, you must deploy and configure sharding before restoring data from the backup. See Deploy a Sharded Cluster for more information.

Additional Resources

See also MongoDB Cloud Manager for seamless automation, backup, and monitoring.