RE: rman backup to disk, mismatch in amount backed up to each cha nnel

  • From: Andy Rivenes <arivenes@xxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Fri, 22 Oct 2004 11:05:23 -0700

I fiddled with this a while back. I believe you'll find that maxpiecesize 
will limit how large an actual file will become (handy if you're trying not 
to exceed 2GB). Maxsetsize will limit how large a set is (which can have 
multiple files). Limiting the set size probably won't help since that's 
related to the number of files per set, which is why the actual set size 
may vary. I don't think there is any restriction on multiple sets per 
channel. Not sure anything can be done automatically to balance the size of 
each channel's destination other than what has already been suggested. 
However, I do believe that RMAN tries to balance the amount written per 
channel, so you could try a finer granularity to your backup. Something 
like filesperset = 1 might work. There may be a disadvantage in speed of 
backup, but ??


At 09:32 AM 10/22/2004, Stephen.Lee@xxxxxxxx wrote:

>A suggestion with no idea if it will work with disk drives.
>Try fiddling with the number of channels in conjunction with the
>maxpiecesize parameter.
>
>allocate channel ch1 type disk maxpiecesize=5000M format 'yada yada';
>allocate channel ch2 type disk maxpiecesize=5000M format 'yada2 yada2';
>allocate channel ch3 type disk maxpiecesize=5000M format 'yada yada';
>allocate channel ch4 type disk maxpiecesize=5000M format 'yada2 yada2';
>
>etc. etc.
>--
>//www.freelists.org/webpage/oracle-l


Andy Rivenes
Email: arivenes@xxxxxxxx

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