Re: Q: Is RAID/striping good with Oracle???
Date: 1996/08/27
Message-ID: <4vv2n9$keg_at_larch.cc.swarthmore.edu>#1/1
In article <4vuv3h$36h_at_lal.interserv.com>,
Bill Meskill <meskillw_at_ncr.disa.mil> wrote:
>I'm running RAID 5 on my HP/UX prod server and wondering
>why you said to stay away from it... Can you elab your
>experience/finding?
>
>Thanks
>Bill Meskill
>meskillw_at_ncr.disa.mil
Common wisdom has it that there is a significant write penaltly with Raid5. I've also heard some suggest that you will lose the entire raid volume if you lose two drives - I'm not sure that is any more likely than losing both drives in a mirrored set.
If you run RAID5 on a transaction system without a caching controller with a fairly large cache, you will see a performance hit. If your system is a read intensive DSS, that shouldn't be as true (of course, Oracle is still doing writes for sorts, etc). I read something when I was configuring our server that you need something on the order of a 40mb write cache on the controller to eliminate most of the RAID5 write penalty. Of course, then you have to weigh the cost of more drives (RAID0+1) vs more costly controller hardware for Raid5.
Glenn Stauffer
DBA
Swarthmore College
Received on Tue Aug 27 1996 - 00:00:00 CEST