Help on STRIPING (AIX) DB objects....

Hi all,

     I'm running Oracle 7.0.16.6.0 on an RS/6000 980B with AIX 3.2.5. We have a 60 Gigabyte Database, that will expand to over 100 Gig by year-end.

We've had some disk contention issues, and although initially we were somewhat hesitant to stripe (due to recovery nightmares), we are now considering striping a bit more of the database to help ease the disk load.

I've done some analysis of striping on our system and wanted to share/get feedback from others:

Assumption: Our PP (Physical Partition) size is 32M. This was recommended

	     by Oracle and IBM at one point, although I'd really appreciated
   	     hearing from other AIX sites.  Seems a smaller PP would be 
	     better for striping.

2nd Assmptn: Our system is largely batch-processing.

Our full-table scans were about 20% LONGER on STRIPED volumes (yes, they were worse). Presumably because the seek times on the other disks were longer than the straight throughput on the disk containing the table... This would lead me to conclude the following:

Never stripe on-line redo-logs, since they are written in a sequential manner.. Instead put 1 on disk 1, then 2 on disk 2, etc. Or should we put them all on the same disk, since it is sequential.... Simply archive off to another disk. (The Archiving is the only issue where I see reading/ writing contention).... Perhaps use disk 1,2,1,2,1 etc.....

With any batch processing, the tables should be on the same physical volume.

If we are doing batch, are the rollback segments going to benefit from being striped? I would think not.... We do not have many users simultaneously updating (All of our data is loaded nightly via one thread).

Any experiences having one or two index tablespaces that are striped and just throwing all indexes into them and hoping for the best?

Any experience is greatly appreciated,
seems I'm getting ambiguous answers from all vendors involved...

Thank you,

David Pinkus

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David Pinkus
Database Systems Consultant
dpinkus_at_netcom.com

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