RMAN vs. Traditional Backup Methods
There are very few reasons not to use RMAN as your main tool for managing backups. Here are
some of the major features of RMAN that are either not available with traditional backup methods
or have significant restrictions using traditional backup methods:
Skip unused blocks Blocks that have never been written to, such as blocks above the
high water mark (HWM) in a table, are not backed up by RMAN when the backup is an
RMAN backupset. Traditional backup methods have no way to know which blocks have
been used.
Backup compression In addition to skipping blocks that have never been used, RMAN
can also use an Oracle-specific binary compression mode to save space on the backup
device. Although operating system??“specific compression techniques are available with
traditional backup methods, the compression algorithm used by RMAN is customized
to maximize the compression for the typical kinds of data found in Oracle data blocks.
Although there is a slight increase in CPU time during an RMAN compressed backup or
recovery operation, the amount of media used for backup may be significantly reduced, as
well as network bandwidth if the backup is performed over the network. Multiple CPUs
can be configured for an RMAN backup to help alleviate the compression overhead.
Open database backups Tablespace backups can be performed in RMAN without using
the begin/end backup clause with alter tablespace.
Pages:
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655