The master database is backed up in the same way as a user database, and it should be dumped regularly and frequently. Make sure that you back up master after changes that update system tables have been made. (For example, back up the master database after these statements are used: ALTER DATABASE, CREATE DATABASE, DISK INIT, DISK RESIZE, various DBCC options such as SHRINKDB, the sp_configure system stored procedure).
The backups of the master database help in recovery if master fails; however, the recovery method for a damaged master database differs from that for user databases. For information about restoring the master database, see the Microsoft SQL Server Administrator's Companion.
Note The master database contains the system catalog, which is the most important information about your SQL Server configuration. Because the master database cannot be separated from its transaction log, you can back up the master database only with the DATABASE option.