Is this a network issue?
I have a mirroring setup - synchronous with automatic failover. The databases went into Disconnected mode for about a minute last night, and everything was synchronized soon after. Looking at the error logs, the principal server could not contact the secondary server. The secondary server could not contact the witness. But I don't see a message that the principal lost contact with the witness.
There weren't any index defrag jobs running, or heavy activity at the time. This is the first time the issue has happened around that time of day.
Principal error log
12:04:06 AM Database mirroring connection error 4 '64(The specified network name is no longer available.)' for 'TCP://prod02.dg.com:5023'.
12:04:27 AM Database mirroring connection error 2 'Connection attempt failed with error: '10060(A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)'.' for 'TCP://prod02.dg.com:5023'.
Secondary error log
12:03:46 AM Database mirroring connection error 4 'An error occurred while receiving data: '64(The specified network name is no longer available.)'.' for 'TCP://PROD-WITNESS.dg.com:5024'.
12:03:46 AM Database mirroring connection error 4 '10054(An existing connection was forcibly closed by the remote host.)' for 'TCP://prod01.dg.com:5022'.
I am responsible for doing a root cause analysis, and am in a DBA role. Does this look like a network issue? If so, is there anything I can suggest that my IT department look into to pinpoint the problem? We've had similar issues intermittently, and they haven't found anything. We use VMWare.
How can I tell if there was a loss of quorum in a mirroring session? There were application timeout errors, and trying to determine whether these were due to the mirroring issues, or just the network. Any thoughts you have would be appreciated.