SLUG Mailing List Archives
Re: [SLUG] RAID Performance Oddness
- To: Peter Chubb <peterc@xxxxxxxxxxxxxxxxxx>
- Subject: Re: [SLUG] RAID Performance Oddness
- From: Craig Dibble <craig@xxxxxxxxxxx>
- Date: Mon, 26 Feb 2007 17:03:50 +1100
- Cc: "slug@xxxxxxxxxxx" <slug@xxxxxxxxxxx>
- User-agent: Thunderbird 184.108.40.206 (X11/20070103)
Peter Chubb wrote:
> I'd suggest having a look at the disk scheduler. If you're using AS,
> try deadline instead. Otherwise write performance can suck for this
> kind of setup (AS is really aimed at a single-user machine).
> # cat /sys/block/sda/queue/scheduler
> noop [anticipatory] deadline cfq
> ^^^^ This can be bad on RAID if you're a server.
Nice thought, and something I hadn't checked, but unfortunately:
# cat /sys/block/cciss\!c0d1/queue/scheduler
noop anticipatory deadline [cfq]
Changing it to deadline showed no appreciable difference in the results,
but neither did any of the others.
I may be missing something (or showing my ignorance), but should I be
expecting to see a difference here given that this is hardware RAID?