Date: Sat, 21 Aug 2010 19:37:31 +0100 From: Bruce Cran <bruce@cran.org.uk> To: Steffen Neubauer <stefreak@stefreak.de> Cc: freebsd-questions@freebsd.org Subject: Re: IO fluctuation Message-ID: <20100821193731.00004505@unknown> In-Reply-To: <4C701AF1.7030304@stefreak.de> References: <4C701170.9080306@stefreak.de> <AANLkTimNEqh6ewUuuFhgP15W=bgnSqqx=KGU8AdgArW1@mail.gmail.com> <4C701AF1.7030304@stefreak.de>
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On Sat, 21 Aug 2010 20:29:05 +0200 Steffen Neubauer <stefreak@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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