From: Daiminger, Helmut (HELMUT.DAIMINGER@wwk.de)
Date: Mon Dec 29 2003 - 07:18:48 EST
Hi Stuart,
the answer is: it all depends... ;)
Of course Oracle performance is better if you distribute your data files
across as many disks as possible (as a rule of thumb). But it is important
to know the I/O behavior of your application.
If you don't want to do SAME, then make sure that th eonline and archived
redo logs are put on separate physical disks (because of the sequential I/O
pattern on them). Data tablespaces usually get random I/O.
If you have an Oracle DBA on site, ask him to find out the database tables
that get most of the I/Os. Usually, about 10% of the tables get 95% of the
I/Os. Then you can think about moving some specific tables to differenty
physical disks.
hth,
Helmut
-----Original Message-----
From: Abramson, Stuart [mailto:SAbramson@Wabtec.com]
Sent: Monday, December 22, 2003 7:07 PM
To: Hpux-Admin (hpux-admin@dutchworks.nl); EMC List (E-mail)
(emc_list@yahoogroups.com)
Subject: [HPADM] Oracle Database on separate physical disks
All:
We had some performance problems recently and discovered that one of our
Oracle Databases, although carefully distributed across some 35 different
HyperVolumes, was actually jammed onto only 5 EMC physical disks.
(We filled out Symmetrix frame in "chuncks", 50 disks on initial delivery,
20 more, 20 more, etc..)
Now, I know that all reads and writes from cache. But is there any value in
actually distributing the Oracle Database file systems across separate
PHYSICAL DISKS.
Please don't tell me about Oracle SAME (Stripe and Mirror Everything).
We're NOT interested in doing that.
We're also not interested in doing the entire Symm as striped meta-volumes.
Stuart
Stuart Abramson | Off: 412/825-1434 | Cell: 412/417-1567 | email:
sabramson@wabtec.com
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