Removing Database Mirroring
The database owner can manually stop a database mirroring session at any time, at either partner.
Impact of Removing Mirroring
When mirroring is removed, the following occurs:
The relationship between the partners and between each partner and the witness breaks permanently, if any relationship exists.
If the partners are communicating with each other when the session is stopped, their relationship is immediately broken on both computers. If the partners are not communicating (the database is in a DISCONNECTED state at the time of stopping), the relationship is broken immediately on the partner from which mirroring is stopped; when the other partner tries to reconnect, it discovers that the database mirroring session has ended.
Information about the mirroring session is dropped, unlike when pausing a session. Mirroring is removed on both the principal database and the mirror database. In sys.databases, the mirroring_state column and all other mirroring columns are set to NULL. For more information, see sys.database_mirroring (Transact-SQL).
Each partner server instance is left with a separate copy of the database.
The mirror database is left in the RESTORING state (see the state column of sys.databases), because the mirror database was created by using RESTORE WITH NORECOVERY. At this point, you can drop the former mirror database or restore it using WITH RECOVERY. When you recover the database, it will have diverged from the former principal database because the recovery starts a new recovery fork. For more information about recovery forks, see Recovery Paths.
To continue mirroring after stopping a session, you must establish a new database mirroring session. If you create a log backup after stopping mirroring, apply it to the mirror database before restarting mirroring. For more information about starting mirroring, see How to: Configure a Database Mirroring Session (SQL Server Management Studio) or Setting Up Database Mirroring.