Before I test the SQL Server 2005 mirror failover, I would like to know any case that after SQL Server failover to mirror server and can't fail back to the primary DB? I want to test it before application code implement failover coding. I can also make sure the DB failover is working under my expectation. In case the mirror DB can't fail back to primary DB, our application is not going to work anymore as it cna't find the new mirror DB. if it can failover without any problem. then I am ok with this. But what if it can't. Any one please share your experience.