We are trying to get to the bottom of our issue. We have a service that connects as MyDomain\ServiceAdmin to a SQL 2008 database.
I believe we have just setup database mirroring too in case the DB/network goes down and we lose connectivity, but we most likely have not tested it.
We had various network issues and then maybe 30+ min later, the service failed and could not connect, saying "Login failed for MyDomain\ServiceAdmin" in the event viewer.
I connect to SQL and the server is running, the DB is there, but the user is not there under (DB>Security>Users) in SQL. Our DBA re-adds the user, and everything works.
DBA is pointing to network issues causing the problem and the user missing. Is that possible or are the network issues just a coincidence and he's trying to CYA?