Database is not synchronizing between the primary and secondary replicas in an Always On Availability Group

 

 

 

If your database is not synchronizing between the primary and secondary replicas in an Always On Availability Group, there may be several reasons why this is happening. Here are some possible causes and solutions:

 

Check the replica synchronization state:

First, check the status of the primary and secondary replicas to see if they are both online and healthy. You can do this by checking the replica state using the "sys.dm_hadr_database_replica_states" dynamic management view or by checking the Always On Dashboard in SQL Server Management Studio. If the replica synchronization state is not healthy or if there are synchronization issues, you can try to troubleshoot the issue by looking at the error messages or event logs.

 

Check the network connectivity:

Always On Availability Groups require a reliable and fast network connection between the primary and secondary replicas. Make sure that there are no network connectivity issues or that there is no firewall blocking the network traffic between the replicas. You can check the network connectivity using the "ping" command or by running network diagnostic tools.

 

Check the database settings:

Check the database settings to make sure that they are configured correctly. Make sure that the database is set up for automatic failover and that the secondary replica is configured as a readable secondary replica.

 

Check the SQL Server logs:

 Check the SQL Server error logs for any relevant error messages or events that might be causing the synchronization issue. Look for errors related to the Always On Availability Groups, such as errors related to the backup or restore process or errors related to the replication process.

 

Check the disk space:

Make sure that there is enough disk space available on both the primary and secondary replicas. If the disk space is low, it can cause synchronization issues or other problems with the database.

 

Restart the synchronization:

 If you have tried all the above steps and still can't synchronize the database, you can try restarting the synchronization process. You can do this by removing the secondary replica from the availability group, re-initializing the replica, and then adding it back to the availability group.