Resolving Disconnected SQL Server Mirrors

On more than one occasion I’ve had a SQL Server mirror disconnect and reconnect repeatedly over a short amount of time, due to an unstable connection between the Principal and Mirror databases.  Usually, this resolves quite quickly and the Mirror will begin re-synchronizing on its own.

Occasionally, however, the mirror would get into a state where it believed it was disconnected, even though the connection between the two instances was up and stable.  When this occurs, you can usually resolve the issue by simply restarting the mirroring endpoints.

First, find the name of the endpoint, if you do not already know it, but issuing this command from the Principal side:

SELECT [name] FROM [sys].[database_mirroring_endpoints]

Then, using the name returned from that simple query, issue the following two commands back-to-back (replacing the endpoint name with your own):


In each of my cases, this has immediately resolved this issue and caused SQL Server to resume synchronizing the mirror.  I hope this helps.

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