Oracle disk subsystem - 10KRPM vs. 15KRPM drive question

From: Thanassis Stathopoulos <thstath_at_attglobal.net>
Date: 6 Mar 2002 07:26:40 -0800
Message-ID: <24426093.0203060726.48a49ea6@posting.google.com>

Hello,

We're considering a rather beefy RAID-10 disk subsystem for an Oracle 9i installation as follows:

8 or 10 pairs of Ultra160 drives with each pair peer connected to a separate SCSI channel for the main stripe sets (2 stripe sets, 64 and 256Kb as per Jonathan Lewis's book)
A pair of mirrored Ultra160 drives for online redo, on their own SCSI channel
Another pair of large, mirrored Ultra160 drives for archive logs, again on their separate SCSI channel

Question: What about the relative benefit of opting for 15KRPM vs. 10KRPM drives for this setup? Rotational speed difference gives a theoretical performance advantage of 50% to the faster drive at roughly twice the price. Can anybody comment, based on their experience, to which extent is this advantage observable in terms of Oracle I/O, assuming 128Mb of RAID cache, a 50/50 OLTP/query scenario, a carefully tuned application and the instance dedicated to it? Asking for your own experiences rather than an absolute guideline.

Thank you for any and all pointers!

Thanassis Received on Wed Mar 06 2002 - 09:26:40 CST