Our web application suffers DB query timeouts a few times a day at random times. Can you help to work out the cause, e.g. deadlocks, mirroring (disk or network), etc?
We have two identical database servers (and a third witness server) with MSSQL 2008 R2 mirroring in high safety mode with automatic failover. Two DBs are mirrored and each server is principal in one so in the event of a failure, both DBs will run from one server. As far as I can see, the problem only occurs on one of these two databases.
Using performance monitor, I can see the "Log Harden Time (ms)" on the principal server spikes to 212,301.206ms at the exact time a timeout occurred (07:30 today). The average from a 24hr period is 22.712ms.
What else should I be looking at to determine the cause of this slowdown?