SQL Server 2008 Mirroring Pauses without warning

Question

I have several databases mirroring with a witness. All 3 machines are local to our network and have generous nics. Monitoring the mirroring, it does not seem like there is a lot of network traffic.

Yet some of the databases' mirroring is pausing without warning. When I restart them, they pause again almost immediately.

What could be the culprit?

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EDIT:

Well, now it looks like they are mirroring again...when I went into mirroring manager and tried restarting them, it succeeded now--whereas yesterday it would automatically pause again.

Anyone know why mirrors would just pause? Wouldn't they just failover?

Answer 1

If you query the sys.database_mirroring catalog view you should find out the status of database mirroring from the mirroring_state field. Try this:

select 
    DB_NAME(database_id),
    mirroring_state
from sys.database_mirroring

When it "pauses", what does the mirroring_state show? Here is a legend:

0 = Suspended

1 = Disconnected from the other partner

2 = Synchronizing

3 = Pending Failover

4 = Synchronized

5 = The partners are not synchronized. Failover is not possible now.

6 = The partners are synchronized. Failover is potentially possible. For information about the requirements for failover see, Synchronous Database Mirroring (High-Safety Mode).

NULL = Database is inaccessible or is not mirrored.