Re: Q: Is RAID/striping good with Oracle???

Thanks for the response Glenn.

You're right about the write penalty. I'd estimate we have a 500:1 read to write ratio (I'm not exaggerating) for our system so hopefully we're okay with RAID 5.

We're actually running with 2 RAID systems and I separated the table data on 1 array and the indexes on the other and then just spread then rest of the DBFs across the two RAID arrays.

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
Received on Tue Aug 27 1996 - 00:00:00 CEST