RE: RMAN backup to tape and blksize
- From: "Mercadante, Thomas F" <thomas.mercadante@xxxxxxxxxxxxxxxxx>
- To: "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 7 Jul 2004 15:38:38 -0400
Stephen,
It is not required. And it has nothing to do with the tape block size.
It has everything to do with the size of the blocks that Oracle creates
before it sends them off to the media software. I think the default size is
64k (I could be wrong here - this is completely from memory).
By increasing the blksize param, Rman creates larger blocks of stuff. So,
instead of sending 100 64K blocks, you could send 10 640K blocks. The
tradeoff is less network io for more in-memory work. I remember testing
this in the early 8.1 days, and found that the a blocksize of about 2million
bytes was the most efficient for my machine - larger than that did not help.
Smaller took more time to complete a backup.
Hope this helps.
Tom Mercadante
Oracle Certified Professional
-----Original Message-----
From: Stephen.Lee@xxxxxxxx [mailto:Stephen.Lee@xxxxxxxx]
Sent: Wednesday, July 07, 2004 3:29 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: RMAN backup to tape and blksize
> -----Original Message-----
> Can someone please shed some light on how to pass the blksize
> parameter to rman on the channel allocation?
I am curious as to which media managment software requires this parameter.
As far as I know, media management software handles tape however it handles
tapes.
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