Sql-server – SQL Server 2008 commit overhead warnings

mirroringsql serversql-server-2008

I have four mirrored user DB's on a pair of Server 2008 R2 machines. My Db engine is SQL Server 2008. Of the four Db's one is warning me of overhead commit latencies ( > 20ms). From some research on the web I see many references of a "redo queue".

I was hoping some one could explain to me what is a redo queue and how can I monitor its behavior.

Best Answer

Using performance monitor in windows you can for example watch the redo queue. Also any other db monitoring tool would help.

The next sentence explains the redo queue, since I can't do it better than msdn here the quote: "The mirror server immediately writes the incoming log to disk, where it is held until it is applied to the mirror database. The log waiting on the mirror's disk is known as the redo queue."

( https://technet.microsoft.com/en-us/library/ms189901%28v=sql.105%29.aspx )