Backup and recovery concepts Overview
Transaction Transaction log backups are only available for the full and bulk-load
recovery options. In this operation, the inactive portion of the transaction log is backed up. Four options are available when you select transaction log backup:
Back up and truncate transaction log.
Back up transaction log, but do not truncate it.
Truncate the transaction log, but do not back it up. (SQL Server 7 and
SQL Server 2000 only)
Back up and restore tail log. (SQL Server 2005 only)
The third option is not a backup at all. It just provides a convenient way to truncate the transaction log for you. It is typically used after a full database backup. The last option is a backup but it does not create a permanent backup image. A backup and a restore of the tail end of the log is typically used following a page-level restore when the database is recovered, but all of the filegroups have not been brought back on line. By backing up and recovering the tail end of the log, SQL Server is able to bring the database back to a usable state.
In addition to database backups, you can use separate images to back up the logical filegroups and files that comprise databases.
There are three ways in which filegroups can be backed up:
This is a backup created from a single filegroup. Scripts for filegroup backups are created when you select individual filegroups in the object browser of the backup database dialog box.
Read-Write Filegroups Backups (SQL Server 2005 only)
This is a backup that contains only the read-write filegroups in a database. If all of the filegroups in a database are read-write, then the read-write filegroup backup will have the same content as a full database backup. Scripts for read-write filegroup backups are created when you select individual databases in the object browser of the backup database dialog box and choose the type of backup as 'read/write filegroups'.