level of protection for your data
The restore-only and roll-forward methods provide different points of
recovery.
- Fast recovery
- This method involves making an offline, full database backup image of the
database at scheduled times. The backup image of the database is only
as current as the time that the last backup was made. For instance, if
you make a backup image at the end of each day and you lose the database
midway through the next day, you will lose a half-day's worth of
changes.
- Complete recovery (also called roll-forward recovery)
- In this method, changes made to the database are retained in logs.
You first restore the database using a backup image; then you use the
logs to reapply changes that were made to the database since the backup image
was created.
With complete recovery selected, you can take advantage of online
backup. For full database recovery, you can choose to recover to the
end of the logs or to a specified point in time. For instance, if an
application corrupted the database, you could start with a restored copy of
the database, and roll-forward changes up until just before that application
started. All units of work in the logs after the time specified will
not be reapplied.