Transaction Log Backup and Restore

A transaction log backup makes a copy of only the log file. A log file backup by itself cannot be used to restore a database. It is used after a database restore to recover the database to the point of the original failure. For example, assume a site performs a database backup on Sunday night and a log backup on each of the other nights. If one of the data disks for the database is lost at 2:30 P.M. Tuesday, the site can:

  1. Back up the current transaction log.
  2. Restore the database backup from Sunday night.
  3. Restore the log backup from Monday night to roll the database forward.
  4. Restore the log backup taken after the failure. This will roll the database forward to the time of the failure.

A transaction log recovery requires an unbroken chain of transaction log backups from the time of the database backup to the time of the failure.

See Also

Transaction Log Backups

  


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