How to: Resume a Database Mirroring Session (Transact-SQL)
At any time, the database owner can resume a suspended database mirroring session.
Following a forced service, when the original principal server reconnects mirroring is suspended. Resuming mirroring in this situation could possibly cause data loss on the original principal server. For information about managing the potential data loss, see Forced Service (with Possible Data Loss).
To resume a database mirroring session
Connect to either partner.
Issue the following Transact-SQL statement:
ALTER DATABASE <database_name> SET PARTNER RESUME
where <database_name> is the mirrored database whose session you want to resume.
Resuming database mirroring places the mirror database in the SYNCHRONIZING state. If the safety level is FULL, the mirror catches up with the principal and the mirror database enters the SYNCHRONIZED state. At this point, failover becomes possible. If the witness is present and ON, automatic failover is possible. In the absence of a witness, manual failover is possible.