Backup levels that ontape supports
The ontape utility supports level-0, level-1, and level-2 backups.
For information about scheduling backups, see Plan a recovery strategy.
Tip: Establish a backup
schedule that keeps level-1 and level-2 backups small. Schedule frequent
level-0 backups to avoid restoring large level-1 and level-2 backups
or many logical-log backups.
- Level-0 backup
- When a fire or flood, for example, completely destroys a computer,
you need a level-0 backup to completely restore database server data
on the replacement computer. For online backups, the data on the backup
tape reflects the contents of the storage spaces at the time the level-0
backup began. (The time the backup started could reflect the last
checkpoint before the backup started.)
A level-0 backup can consume lots of time because ontape must write all the pages to tape.
- Level-1 backup
- A level-1 backup usually takes less time than a level-0 backup because you copy only part of the database server data to the backup tape.
- Level-2 backup
- A level-2 backup after a level-1 backup usually takes less time than another level-1 backup because only the changes made after the last level-1 backup (instead of the last level-0) get copied to the backup tape.