Tugger the SLUGger!SLUG Mailing List Archives

Re: [SLUG] RAID Performance Oddness

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?