A live backup is a continuous backup of the database that helps protect against total computer failure. You can use the redundant copy of the transaction log to restart your system on a secondary computer.

If your system fails, the backed up transaction log can be used for a rapid restart of the system. However, depending on the load that the database server is processing, the live backup may lag behind and may not contain all committed transactions.

An alternative to a live backup is to use database mirroring. See Introduction to database mirroring.

You should normally run the dbbackup utility from the secondary computer.

If the primary computer becomes unusable, you can restart your database using the secondary computer. The database file and the transaction log hold the information needed to restart the database.

Live backups and regular backups

The live backup of the transaction log is always the same length or shorter than the active transaction log. When a live backup is running, and another backup restarts the transaction log (dbbackup -r or dbbackup -x), the live backup automatically truncates the live backup log and restarts the live backup at the beginning of the new transaction log.

See also

• Make a live backup
• Restart from a live backup
• Types of backup