Force Service in a Database Mirroring Session (Transact-SQL)
Applies To: SQL Server 2016
In high-performance mode and high-safety mode without automatic failover, if the principal server fails while the mirror server is available, the database owner can make the database available by forcing service to fail over (with possible data loss) to the mirror database. This option is available only under all the following conditions:
The principal server is down.
WITNESS is set to OFF or is connected to the mirror server.
Forcing service suspends the session and starts a new recovery fork. The effect of forcing service is similar to removing mirroring and recovering the former principal database. However, forcing service facilitates resynchronizing the databases (with possible data loss) when mirroring resumes.
Connect to the mirror server.
Issue the following statement:
ALTER DATABASE <database_name> SET PARTNER FORCE_SERVICE_ALLOW_DATA_LOSS
where <database_name> is the mirrored database.
The mirror server immediately transitions to principal server, and mirroring is suspended.