Database Manual / Self-Managed Deployments / Administration / Backup Methods

Back Up and Restore a Self-Managed Deployment with MongoDB Tools

This tutorial describes the process for creating backups and restoring data using the command-line utilities mongorestore and mongodump provided with MongoDB.

To restore a backup of your self-hosted deployment to a managed MongoDB Atlas deployment, see Seed with mongorestore.

For a fully-managed backup method, use Cloud Backups in MongoDB Atlas, which provide localized backup storage using the native snapshot functionality of the cluster's cloud service provider.

Considerations

Deployments

The mongorestore and mongodump utilities work with BSON data dumps, and are useful for creating backups of small deployments. For resilient and non-disruptive backups, use file system snapshots or block-level disk snapshots with Cloud Backups from MongoDB Atlas.

Note

Back Up Sharded Clusters with MongoDB Atlas

To use mongodump and mongorestore as a backup strategy for sharded clusters, see Back Up a Self-Managed Sharded Cluster with a Database Dump.

Sharded clusters can also use one of the following coordinated backup and restore processes, which maintain the atomicity guarantees of transactions across shards:

Performance Impacts

Because mongodump and mongorestore operate by interacting with a running mongod instance, they can impact the performance of your running database. Not only do the tools create traffic for a running database instance, they also force the database to read all data through memory. When MongoDB reads infrequently used data, it can evict more frequently accessed data, causing a deterioration in performance for the database's regular workload.

When backing up your data with MongoDB's tools, consider the following guidelines:

  • Label files so that you can identify the contents of the backup as well as the point in time that the backup reflects.
  • Use an alternative backup strategy such as Filesystem Snapshots or Cloud Backups in MongoDB Atlas if the performance impact of mongodump and mongorestore is unacceptable for your use case.

  • To ensure mongodump can take a consistent backup of a replica set, you must either use the --oplog option to capture writes received during backup operations or stop all writes to the replica set for the duration of the backup.

    For sharded cluster replica sets, see Back Up a Self-Managed Sharded Cluster with a Database Dump.

  • Ensure that your backups are usable by restoring them to a test MongoDB deployment.
  • To help reduce the likelihood of inconsistencies in a sharded cluster backup, you must stop the balancer, stop all write operations, and stop any schema transformations for the duration of the backup.

Tip

Backup Methods for a Self-Managed Deployment and MongoDB Atlas Cloud Backups for more information on backing up MongoDB instances. Additionally, consider the following reference documentation for the MongoDB Database Tools:

Output Format

mongorestore and mongodump can output data to an archive file, which is a single-file alternative to multiple BSON files. Archive files are special-purpose formats that support non-contiguous file writes. They enable concurrent backups from MongoDB, as well as restores to MongoDB. Using archive files optimizes disk I/O while backup and restore operations execute.

You can also output archive files to the standard output (stdout). Writing to the standard output allows for data migration over networks, reduced disk I/O footprint, and concurrency gains in both the MongoDB tools and your storage engine.

For more information on archive files, see the --archive option.

Stale Backups

Backups provide a snapshot of the current state of the database. When you restore from a backup, the restored database doesn't include any changes made after the backup was taken, which can result in data loss.

Procedures

Back Up a Database with mongodump

Note

Back Up Sharded Clusters with MongoDB Atlas

To use mongodump and mongorestore as a backup strategy for sharded clusters, see Back Up a Self-Managed Sharded Cluster with a Database Dump.

Sharded clusters can also use one of the following coordinated backup and restore processes, which maintain the atomicity guarantees of transactions across shards:

Exclude local Database

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

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.

The backup role provides additional privileges to back up the system.profile collection that exists when running with database profiling.

Basic mongodump Operations

The mongodump utility backs up data by connecting to a running mongod.

The utility can create a backup for an entire server, database or collection, or can use a query to backup just part of a collection.

When you run mongodump without any arguments, the command connects to the MongoDB instance on the local system (e.g. localhost) on port 27017 and creates a database backup named dump/ in the current directory.

To backup data from a mongod instance running on the same machine and on the default port of 27017, use the following command:

mongodump

To specify the host and port of the MongoDB instance, you can either:

  • Specify the hostname and port in the --uri string, using either an SRV or standard connection string:

    mongodump --uri="mongodb+srv://username:password@cluster0.example.mongodb.net" <additional_options>

  • Specify the hostname and port in the --host string:

    mongodump --host="mongodb0.example.com:27017" <additional_options>

  • Specify the hostname and port in the --host and --port:

    mongodump --host="mongodb0.example.com" --port=27017 <additional_options>

mongodump will write BSON files that hold a copy of data accessible via the mongod listening on port 27017 of the mongodb.example.net host. See Create Backups from Non-Local mongod Instances for more information.

To specify a different output directory, you can use the --out or -o option:

mongodump --out=/opt/backup/mongodump-1

To limit the amount of data included in the database dump, you can specify --db and --collection as options to mongodump. For example:

mongodump --collection=myCollection --db=test

This operation creates a dump of the collection named myCollection from the database test in a dump/ subdirectory of the current working directory.

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.

Create Backups Using Oplogs

The --oplog option with mongodump collects the oplog entries and allows you to perform a backup on a live database. If you later restore the database from the backup, the database will be the same as it was when the backup process completed.

With --oplog, mongodump copies all the data from the source database as well as all of the oplog entries from the beginning to the end of the backup procedure. This operation, in conjunction with mongorestore --oplogReplay, allows you to restore a backup that reflects the specific moment in time that corresponds to when mongodump completed creating the dump file.

Create Backups from Non-Local mongod Instances

The --host and --port options for mongodump allow you to connect to and backup from a remote host. Consider the following example:

mongodump \
   --host=mongodb1.example.net \
   --port=3017 \
   --username=user \
   --password="pass" \
   --out=/opt/backup/mongodump-1

On any mongodump command you may, as above, specify username and password credentials to specify database authentication.

Restore a Database with mongorestore

Note

Back Up Sharded Clusters with MongoDB Atlas

To use mongodump and mongorestore as a backup strategy for sharded clusters, see Back Up a Self-Managed Sharded Cluster with a Database Dump.

Sharded clusters can also use one of the following coordinated backup and restore processes, which maintain the atomicity guarantees of transactions across shards:

Access Control

To restore data to a MongoDB deployment that has access control enabled, the restore role provides the necessary privileges to restore data from backups if the data does not include system.profile collection data and you run mongorestore without the --oplogReplay option.

If the backup data includes system.profile collection data or you run with --oplogReplay, you need additional privileges:

system.profile

If the backup data includes system.profile collection data and the target database does not contain the system.profile collection, mongorestore attempts to create the collection even though the program does not actually restore system.profile documents. As such, the user requires additional privileges to perform createCollection and convertToCapped actions on the system.profile collection for a database.

Both the built-in roles dbAdmin and dbAdminAnyDatabase provide the additional privileges.

--oplogReplay

To run with --oplogReplay, create a user-defined role that has anyAction on anyResource.

Grant only to users who must run mongorestore with --oplogReplay.

Basic mongorestore Operations

The mongorestore utility restores a binary backup created by mongodump. By default, mongorestore looks for a database backup in the dump/ directory.

The mongorestore utility restores data by connecting to a running mongod directly.

mongorestore can restore either an entire database backup or a subset of the backup.

Note

All MongoDB collections have UUIDs by default. When MongoDB restores collections, the restored collections retain their original UUIDs. When restoring a collection where no UUID was present, MongoDB generates a UUID for the restored collection.

For more information on collection UUIDs, see Collections.

To use mongorestore to connect to an active mongod, use a command with the following prototype form:

mongorestore --uri <connection string> <path to the backup>

Consider the following example:

mongorestore /opt/backup/mongodump-1

Here, mongorestore imports the database backup in the /opt/backup/mongodump-1 directory to the mongod instance running on the localhost interface on the default port 27017.

Use an Oplog File to Backup and Restore Data

To capture writes that may occur while mongodump is running, use mongodump --oplog. mongodump creates an oplog.bson file with oplog entries for each write that occurred during the run. You can apply the oplog operations with mongorestore --oplogReplay.

For examples, see mongodump Examples and mongorestore Examples.

All of the data from the oplog.bson file is restored.

mongorestore --oplogReplay doesn't allow you to restore data to an arbitrary point in time. Use mongorestore --oplogReplay to ensure the restored data is up to date with any writes that occurred during the mongodump --oplog run.

Note

--oplog is intended for use with replica sets. For sharded clusters, including replica sets that are part of a sharded environment, see Back Up a Self-Managed Sharded Cluster with a Database Dump.

You may also consider using the mongorestore --objcheck option to check the integrity of objects while inserting them into the database, or you may consider the mongorestore --drop option to drop each collection from the database before restoring from backups.

Restore Backups to Non-Local mongod Instances

By default, mongorestore connects to a MongoDB instance running on the localhost interface and on the default port (27017). If you want to restore to a different host or port, use the --host and --port options.

The following example that specifies the --host and --port options:

mongorestore --host=mongodb1.example.net --port=3017

If restoring to an instance that enforces access control, include the --username and the --authenticationDatabase as well. Omit the --password option to have mongorestore prompt for the password:

mongorestore \
   --host=mongodb1.example.net \
   --port=3017 \
   --username=user \
   --authenticationDatabase=admin \
   /opt/backup/mongodump-1