Wednesday, February 3, 2010

Short note on AX and database mirroring in SQL Server 2008

The last days, I have been working with a customer running AX 2009 and SQL Server 2008 SP1 Standard (x64) on Windows Server 2008 SP2. The solution suffered from general performance issues that possibly could have a lot of sources. As usual my attention was around SQL Server and this time I started looking at Wait Stats which showed a waste amount of waits related to mirroring. After some Googling, I was a little bit confused about this beeing normal or not. The nature of database mirroring could in fact result in high Wait Stat values since the processes involved, is mostly sleeping (suspended). But I choosed to consider this as a possible source since the nature of database mirroring in my oppinion, does'nt fit the nature of AX as a classic OLTP application. And since disabling database mirroring is an isolated and low risk operation, we choosed to stop mirroring for all database (around 10). After this, the overall performance increased and the customer reported this almost immediately. It's a little bit early to conclude, but the initial responce seems pretty promising.