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How to automatically sync a member of a replica set in MongoDB?
MongoDB provides two options for performing an initial sync: Restart the mongod with an empty data directory and let MongoDB’s normal initial syncing feature restore the data. This is the more simple option but may take longer to replace the data. See Automatically Sync a Member.
How often does a secondary MongoDB replicate data?
The secondary mongod can restart the initial sync source selection process up to 10 times before exiting with an error. Secondary members replicate data continuously after the initial sync. Secondary members copy the oplog from their sync from source and apply these operations in an asynchronous process. [ 1]
When to resume synchronization in MongoDB 4.4?
Starting in MongoDB 4.4, a secondary performing initial sync can attempt to resume the sync process if interrupted by a transient (i.e. temporary) network error, collection drop, or collection rename. The sync source must also run MongoDB 4.4 to support resumable initial sync.
When to sync MongoDB to empty DATA directory?
Schedule the synchronization during a time of low usage or during a maintenance window. MongoDB provides two options for performing an initial sync: Restart the mongod with an empty data directory and let MongoDB’s normal initial syncing feature restore the data. This is the more simple option but may take longer to replace the data.
What are the requirements for synchronization in MongoDB?
The sync source must have newer oplog entries than the member (i.e. the sync source is ahead of the member). The sync source must be visible. The sync source must be within 30 seconds of the newest oplog entry on the primary. If the member builds indexes, the sync source must build indexes.
What happens when the sync target falls behind mongod?
The mongod instance restarts. The connection between the mongod and the sync target closes. If the sync target falls more than 30 seconds behind another member of the replica set. © MongoDB, Inc 2008-present.
How to automatically sync a member of a replica set?
Restart the mongod with an empty data directory and let MongoDB’s normal initial syncing feature restore the data. This is the more simple option but may take longer to replace the data. See Automatically Sync a Member. Restart the machine with a copy of a recent data directory from another member in the replica set.
What’s the best way to sync data in MongoDB?
MongoDB provides two options for performing an initial sync: Restart the mongod with an empty data directory and let MongoDB’s normal initial syncing feature restore the data. This is the more simple option but may take longer to replace the data.
What happens when you add a new member to MongoDB?
Make sure the new member’s data directory does not contain data. The new member will copy the data from an existing member. If the new member is in a recovering state, it must exit and become a secondary before MongoDB can copy all data as part of the replication process.