Thanks for that. However, when I put this in one tablespace and do an iostat -xtdc 5 5, I see a very high svc_t and %b on just one of the devices. The others have very close to 0. I know the SQL needs some tuning, but why is I/O not spread to the other devices??

________________________________

From: Chamberlain John [mailto:oracledba-ezmlmshield-x26709839.[Email address protected]
Sent: Wed 28/02/2007 10:49
To: LazyDBA Discussion
Subject: RE: INDX or any index tablespace




How about better space management? Theres not much value keeping a table
with only one row in it in a tablespace with a 100MB or more default extent
size. I try to use LMT's with appropriate uniform extent sizes in
tablespaces, grouping similarly sized tables/indexes together. This avoids
both space wastage and excessive fragmentation.

Beyond space management and administration, there is nothing to stop you
putting every table and index in one huge USERS tablespace if you so desire.
On the EMC SAN it wont make much difference to performance either way.

John.

-----Original Message-----
From: Erica Raymond
[mailto:oracledba-ezmlmshield-x54018889.[Email address protected]
Sent: 28 February 2007 09:47
To: LazyDBA Discussion
Subject: INDX or any index tablespace

Hi People,

IS there still the need to use this other than to spread the I/O over
several disks?? We use an EMC SAN and have RAID 1+0 for the disks. In
effect, we know the I/O is somehow spread. However, I also have a schema
whose objects are created in the USERS tablespace. I would want to know the
side effects of this other than Constant fragmentation, ease of
administration and spread of I/O which is taken care of from the SAN cache
reads and writes.

Is there any other reason why we should have the separate tablespaces??

Thanks,

Erica


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