Database mirror monitoring

When a Skype for Business Server 2015 backend SQL server is using database mirroring for high availability, some information on issues with the mirroring relation is required.


Set up Database Mirroring Monitor:
Launch the Database Mirroring Monitor tool



Go to Menu -> Action and select Register Mirrored Database



Select the primary server in the drop down menu and tick all the databases you want to monitor



Select a database and go to Warnings pane, click Set Thresholds



Set thresholds like this



Repeat for every database mirror relation you want to monitor


Now you will get an informational event 32042 in the application event log when the size of unsent transaction exceeds 100KB



And you will recieve an informational event 32040 in the application event log when the age of the oldest unsent transaction surpasses 5 minutes (4 minutes on mirror server)



Now you will add the event log entries to your favorite monitoring tool and you should be covered from this event, if you react properly to these above event

Which occurs when the transaction log is full due to database mirroring stopped.