I agree it "depends", as it does in many situations. We are in a slightly different position here where our setup will need to be used by all of our databases. We will not have the option to customize depending on the system. Luckily we do not have systems with the heavy work load that others on the list probably deal with. Therefore, we are just trying to look for a generic approach that might fit a number of different systems. I was thinking 512 bytes might actually hurt us, while a generic setup with a larger stripe size would be more ideal.
Our current setup is "Here is some RAID-5, have fun that is your only option". We might end up sticking with that option, but have decided to try a generic raid 10 setup to compare it against what we currently have.
From: oracle-l-bounce_at_freelists.org On Behalf Of Rich Jesse
Sent: Friday, September 25, 2009 11:18 AM
Subject: RE: Any good papers on raid 10 setup for oracle?
We are going to be testing some raid 10 and our SAN Admin set the stripe
size to 512 bytes. From what I have read in the past, I was thinking Oracle
would do better off closer to a stripe size of
*multibock_read_count, however it has been awhile since I
looked into it. I know it always depends, but the 512 bytes doesn't sound
correct to me
We went through this not too long ago. The answer is, as usual, "it
depends". It's best for you and your team to experiment with different
values to see which is "best". Keep in mind Oracle's specific IO patterns,
e.g. indexed reads versus full table scans for reading and DBWR versus redos
on the writing.
There are tools like Orion to help evaluate IO. They are a great start to
eliminate some configurations, but I found generating my own SQL gave me
more realistic expectations.
If I sound like I'm being somewhat vague and generic, it's because I am!
This is a HUGE topic that will require you and your team to do their
homework. Like another poster mentioned, involve your vendors! You'll
hopefully find that they are interested in helping you, if only to prevent
some hollering later on... :)
One final note -- even though I view myself as a BAARF-type, I was not able
to justify the expense of RAID-10 over RAID-5 for our little IBM DS5300 SAN
with reasonably beefy POWER6 hardware pushing it, taking into account
performance, reliability, and of course cost. Waaay too brief, I know, but
my point is to thoroughly investigate all of your options.