Image copies are the default backup file
format in RMAN.
This is a great feature of Oracle 11g??™s RMAN for the following reason: If you add another
datafile to a tablespace, you need to also remember to add the new datafile to your Unix script
cp command. By creating image copies using RMAN, all datafiles will automatically be included
in the backup. Forgetting to add the new datafile to a Unix script will make a recovery situation
extremely inconvenient at best and a disaster at worst.
Backupsets and Backup Pieces
In contrast to image copies, which can be created in most any backup environment, backupsets
can be created and restored only with RMAN. A backupset is an RMAN backup of part or all
of a database, consisting of one or more backup pieces. Each backup piece belongs to only
one backupset, and can contain backups of one or many datafiles in the database. All
backupsets and pieces are recorded in the RMAN repository, the same as any other RMANinitiated
backup.
Compressed Backups
For any Oracle11g RMAN backup creating a backupset, compression is available to reduce the
amount of disk space or tape needed to store the backup. Compressed backups are only usable
by RMAN, and they need no special processing when used in a recovery operation; RMAN
Chapter 12: Using Recovery Manager (RMAN) 423
automatically decompresses the backup. Creating compressed backups is as easy as specifying
as compressed backupset in the RMAN backup command.
Pages:
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660