Assume that you have many databases in a distributed Always On availability groups (AG) in Microsoft SQL Server 2016 and 2017. When you perform a manual failover over the second AG between forwarder and secondary replica, you will notice that it may fail even though all replicas are synchronized. Additionally, you will receive error messages that resemble the following:
Msg 41104, Level 16, State 12, Line LineNumber
Failover of the availability group to the local replica failed because the availability group resource did not come online due to a previous error.
To identify the error, you can check the SQL Server error log, the Windows Server Failover Cluster logs and system event logs. For more information about how to view events and logs for a Windows Server Failover Clustering (WSFC) cluster, you can see Windows Server documentation. When you check the error log, you will find an error message that resembles the following:
The availability replica for
availability group '<AGName>' on this instance of SQL Server cannot become the primary replica. One or more
databases are not synchronized or have not joined the availability group.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
The issue is fixed in the following cumulative updates for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the
hotfixes and all the security fixes that were included with the previous
cumulative update. Check out the latest cumulative updates for SQL Server:
Learn about the terminology that Microsoft uses to describe software updates.