The system databases need to be backed up just as user databases are backed up. This allows the system to be rebuilt in the event of system or database failure, for example, if a hard disk fails. It is important to have regular backups of the following system databases:
Note It is not necessary to back up the tempdb system database because tempdb is rebuilt each time Microsoft® SQL Server™is started. When SQL Server is shut down, any data in tempdb is deleted permanently.