We have a client site that uses SQL Server. The site this morning was slow, and we realised that the primary database server was responsible for a lot of disk activity on tempdb (Server 2008, SQL Server 2008 R2, looking in the resource monitor), which was the reason for the slowness.
In the event log we saw this message every couple of seconds or so:
"Database Mirroring login attempt by user xxxxx failed with 'Connection handshake failed. The login xxxxx does not have connect permission on the endpoint. State 84"
The IT guys say these two things (tempdb being thrashed and a connection failure for the mirroring login) are unrelated - we're not so sure. Anybody say for definite?
P.S. we failed over the db server and the slowness went away, though the amount of disk IO on tempdb continues to rise, and the event log is still getting those error messages every couple of seconds