IO fluctuation
Bruce Cran
bruce at cran.org.uk
Sat Aug 21 18:37:28 UTC 2010
On Sat, 21 Aug 2010 20:29:05 +0200
Steffen Neubauer <stefreak at stefreak.de> wrote:
> So this is not a zfs problem. But I don't think it's the hardware,
> too - I used that mainboard before FreeBSD with no problems.
> And the WD EARS drives can't be the problem on raw device access,
> too, because I used bs=1M, that should be enough...
It _is_ the EARS: the hang is probably the drive spinning back up after
it's turned itself off - it has really aggressive power management by
default.
For more information about the variation, see
http://maycontaintracesofbolts.blogspot.com/2010/08/benchmarking-advanced-format-drives.html
--
Bruce Cran
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