Re: disk layout san raid5

wane wrote:
> We are migrating an Oracle9i (9.2.0.7.0) database to an AIX 5300-04
> LPAR which is allocated disk from a DS4500 which is setup into 2 RAID5
> array groups. The disk is presented to AIX as 2 "LUN"s (or hdisks) with
> one from each RAID5 array group. We are upgrading the third party
> application so we have the opportunity to do a complete exp/imp and
> restucture the disk since a full test cycle will be performed.
> Currently there are a "maze" of tablespaces/datafiles for
> tables/indexes (about 65GB space usage). Oh, and all disk is allocated
> through Virtual I/O LPARs and with a SVC layer in front of the DS4500.
>
> I am proposing to reduce the number of tablespaces (maybe even just 1)
> and use 2 datafiles for each tablespace with each datafile on a
> separate hdisk (ie LUN).
>
> Question: is there any performance advantage to more and smaller
> tablespaces and/or datafiles even though they technically exist on the
> same physical disk?
>
> Any comments would be appraciated. Thanks.

Depending on workload I'd suggest something other than RAID5 but otherwise more LUNs is better but I'd be surprised if changing the number of tablespaces (unless you hade hundreds of them) will make any difference.

PS: Tablespaces don't have sizes ... datafiles do.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org