----- Original Message ----- From: "Todd C. Merrill" tmerrill@mathworks.com To: "Chris Lamb" skeezics@measurecast.com Cc: toasters@mathworks.com Sent: Tuesday, September 12, 2000 10:09 AM Subject: Re: 2 volumes or 1
On Mon, 11 Sep 2000, Bruce Sterling Woodcock wrote:
From: "Chris Lamb" skeezics@measurecast.com
But to turn this thread on a slight tangent, I was curious about the performance advantages of spreading drives within a RAID group across multiple controllers.
[...]
interested too. :-) Given that More Disks Is Bettah, the question
becomes
whether or not it's worth the trouble (on a filer) to try to optimize
the
physical placement of those drives.
Worth the trouble? No.
Worth the trouble? Yes IMHO. The NetApp 202 class notes state:
"A RAID group that spans two different controllers shows a 10% performance degradation."
We've been over this before. This note, as written, is grossly false. The penalty is only on writes, and only noticeable if you're already saturating your NVRAM such that you are writing all the time. There is no constant 10% performance penalty.
Bruce