Back Up to a Mirrored Media Set (Transact-SQL)
This topic describes how to use the Transact-SQL BACKUP statement to specify a mirrored media set when backing up a SQL Server database. In your BACKUP statement, specify the first mirror in the TO clause. Then, specify each mirror in its own MIRROR TO clause. The TO and MIRROR TO clauses must specify the same number and type of backup devices.
The following example creates the mirrored media set illustrated in the previous illustration and backs up the AdventureWorks2012 database to both mirrors.
BACKUP DATABASE AdventureWorks2012 TO TAPE = '\\.\tape0', TAPE = '\\.\tape1' MIRROR TO TAPE = '\\.\tape2', TAPE = '\\.\tape3' WITH FORMAT, MEDIANAME = 'AdventureWorks2012Set1'; GO
To restore from a mirrored backup