RE: RMAN impact

  • From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
  • To: <cosmini@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Wed, 18 Oct 2006 09:13:07 -0700

It basically performs a full scans of all your tables, so lots of "I"
(a.k.a Input), and then writes either to disk (lots of "O", a.k.a
Output) or to tape, depending on how you have it configured.  So, if
you're system is tight on I/O capacity, then yes - a backup of any type,
not only RMAN, could certainly cause performance problems.  And
incremental backups, which are only available with Enterprise Edition,
don't make as much difference as you might expect because they still
require a full scan of all blocks - and then only the updated blocks
since the last full or incremental of level-1 are written out to the
backup device.  That is, unless you're on 10g, where the change tracking
file was introduced to avoid the full scan.  Of course there is
significant CPU involved with all that I/O as well, but usually the I/O
is more of an issue since that's where most systems seem to be
bottlenecked.
 
Regards,
Brandon


________________________________

        From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of cosmin ioan
         
        so, can anyone tell me what kind of impact RMAN usually brings
to a system, rather what toll it takes on one!  :-)
         
         


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