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Restore a Replica Set from MongoDB Backups¶
This procedure outlines the process for taking MongoDB data and restoring that data into a new replica set. Use this approach for seeding test deployments from production backups as well as part of disaster recovery.
You cannot restore a single data set to three new
mongod
instances and then create a replica set. In this
situation MongoDB will force the secondaries to perform an initial
sync. The procedures in this document describe the correct and
efficient ways to deploy a replica set.
Restore Database into a Single Node Replica Set¶
Obtain backup MongoDB Database files.¶
The backup files may come from a file system snapshot. The MongoDB Cloud Manager produces MongoDB database files for stored snapshots and point in time snapshots. For Ops Manager, an on-premise solution available in MongoDB Enterprise Advanced, see also the Ops Manager Backup overview.
You
can also use mongorestore
to restore database files using
data created with mongodump
. See
Back Up and Restore with MongoDB Tools for more information.
Initiate the new replica set.¶
Use rs.initiate()
on one and only one member of the replica set:
MongoDB initiates a set that consists of the current member and that uses the default replica set configuration.
Add Members to the Replica Set¶
MongoDB provides two options for restoring secondary members of a replica set:
- Manually copy the database files to each data directory.
- Allow initial sync to distribute data automatically.
The following sections outlines both approaches.
Note
If your database is large, initial sync can take a long time to complete. For large databases, it might be preferable to copy the database files onto each host.
Copy Database Files and Restart mongod
Instance¶
Use the following sequence of operations to “seed” additional members of the replica set with the restored data by copying MongoDB data files directly.
Shut down the mongod
instance that you restored.¶
Use --shutdown
or
db.shutdownServer()
to ensure a clean shut down.
Add the secondaries to the replica set.¶
In a mongo
shell connected to the primary, add the
secondaries to the replica set using
rs.add()
. See Deploy a Replica Set for more
information about deploying a replica set.
Update Secondaries using Initial Sync¶
Use the following sequence of operations to “seed” additional members of the replica set with the restored data using the default initial sync operation.
Ensure that the data directories on the prospective replica set members are empty.¶
Add each prospective member to the replica set.¶
When you add a member to the replica set, Initial Sync copies the data from the primary to the new member.