RE: RAID system max throughput

From: Jack C. Applewhite <japplewhite_at_inetprofit.com>
Date: Fri, 07 Dec 2001 14:15:46 -0800
Message-ID: <F001.003D7EF6.20011207132523@fatcity.com>

Dennis,

I'm no RAID guru, but I can sure imagine disk heads thrashing around, trying to satisfy a mix of sequential and random reads and writes, causing the DB to wait, but not getting anywhere near the rated throughput for the RAID controller or channel.

Could that possibly be the case?

Jack

Jack C. Applewhite
Database Administrator/Developer
OCP Oracle8 DBA
iNetProfit, Inc.
Austin, Texas
www.iNetProfit.com
japplewhite_at_inetprofit.com
(512)327-9068

-----Original Message-----
WILLIAMS
Sent: Friday, December 07, 2001 10:40 AM To: Multiple recipients of list ORACLE-L

Whenever I discuss disk waits with my system administrator, I always get the reply that "the RAID system isn't anywhere near its rated throughput". Maybe I'm wrong, but I don't see any of the tuning books mentioning that as a relevant performance characteristic. However, I've never been able to move the discussion beyond this point. Can anyone straighten me out on this point or point me to a resource that might be applicable.

Our system is Oracle 8.1.6, Compaq Tru64. We use hardware RAID-5 with a battery-backed RAM cache, and have about 3 RAID sets (plus some extra disks for redo logs, etc.), and performance is fine, but I'm always looking as to how we can improve Oracle performance. The application is our corporate ERP system.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

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Author: Jack C. Applewhite
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Received on Fri Dec 07 2001 - 16:15:46 CST