Recovery is the rebuilding of a database or table space
after a problem such as media or storage failure, power interruption,
or application failure. If you have backed up your database, or individual
table spaces, you can rebuild them should they become damaged or corrupted
in some way.
There are four types of recovery:
- Crash recovery protects a database from being left in an inconsistent,
or unusable, state when transactions (also called units of work) are
interrupted unexpectedly.
- Disaster recovery consist of the process to restore a database
in the event of a fire, earthquake, vandalism, or other catastrophic
events.
- Version recovery is the restoration of a previous version of the
database, using an image that was created during a backup operation.
- Rollforward recovery can be used to reapply changes that were
made by transactions that were committed after a backup was made.
The DB2® database manager
starts crash recovery automatically to attempt to recover a database
after a power interruption. You can use version recovery or rollforward
recovery to recover a damaged database.