Category: Always On

In SQL Server Management Studio, Right click principle database -> properties -> Mirroring, the click Resume button. The alternative way is to right click principle database -> Tasks -> Mirror, the click Resume button.

We can also run the following Transact-SQL query to resume the database mirroring:

ALTER DATABASE userdb SET PARTNER RESUME;

To check the synchronizing progressing by running following Transact-SQL query:

SELECT [counter_name] as CounterName,[cntr_value] as CounterValue
FROM sys.dm_os_performance_counters
WHERE [object_name] LIKE ('%Database Mirroring%')
AND [counter_name] IN ('Log Send Queue KB','Redo Queue KB')
AND [instance_name]='TESTDB';

CounterName	      CounterValue
Redo Queue KB     1260219                                                                                              
Log Send Queue KB 8407945                                                                                      

“Redo Queue KB” : Logs to applied onto mirroring database.
“Log Send Queue KB” : Logs to be sent to mirroring database.

Another alternative way to check mirroring status and statistics:

Right click principle database -> Tasks -> Launch Database Mirroring Monitor.

Click History, you can find when the mirror broke: