On Fri, 11 Apr 2008, Jeff wrote:
Using 4 of these with a dataset of about 30GB across a few files (Machine has
8GB mem) I went from around 100 io/sec to 330 changing to noop. Quite an
improvement. If you have a decent controller CFQ is not what you want. I
tried deadline as well and it was a touch slower. The controller is a 3ware
9550sx with 4 disks in a raid10.
I ran Greg's fadvise test program a while back on a 12-disc array. The
three schedulers (deadline, noop, anticipatory) all performed pretty-much
the same, with the fourth (cfq, the default) being consistently slower.
it also seems changing elevators on the fly works fine (echo schedulername >
/sys/block/.../queue/scheduler I admit I sat there flipping back and forth
going "disk go fast.. disk go slow.. disk go fast... " :)
Oh Homer Simpson, your legacy lives on.
Matthew
--
I suppose some of you have done a Continuous Maths course. Yes? Continuous
Maths? <menacing stares from audience> Whoah, it was like that, was it!
-- Computer Science Lecturer
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