Re: Oracle RAID
Date: Mon, 30 Jan 95 10:25:13 -0500
Message-ID: <Zs-YiHp.sharville_at_delphi.com>
Cynthia Young Pinchot <cry1_at_pge.com> writes:
>Does anyone out there have any experience using RAID with an Oracle database?
>Or is anyone in the process of setting up RAID?
I have all the rollbacks, logs, etc on raid1 (mirroring) and the rest on raid5
(striping). I have indexes on different stripes than the data. Raid1 is better
for write intensive apps, raid5 is better for read intensive apps. That's
because (on DG) the writes to a mirrored pair can happen in async mode. Writes
to a stripe require 1 data write and 1 parity write. Conversly, 5 heads can
read a stripe at the same time, getting different data on each head.
I have 10 gig on a DG clariion raid box. The unix read and write buffers show
100% hit ratio almost all the time. I ran it using raw I/O for a while and
decided there was not enough performance gain to outweigh the advantages of
the unix file system (which is pretty sophisticated in DGUX 5.4r3.10).
Steve Harville
Stemco Inc
Longview, TX
sharville_at_delphi.com
Received on Mon Jan 30 1995 - 16:25:13 CET