Date: Thu, 08 Aug 2013 22:04:07 +0100 From: Frank Leonhardt <frank2@fjl.co.uk> To: freebsd-questions@freebsd.org Subject: Re: Terrible disk performance with LSI / FreeBSD 9.2-RC1 Message-ID: <520407C7.9080603@fjl.co.uk> In-Reply-To: <02C07E9F-ABB3-4A38-9638-21F913A08EC1@elde.net> References: <CABXB=RSRnB41yjq5Qcbiz-JCRssNwx2AatJ2Dn%2BHhuD9GaBh%2Bw@mail.gmail.com> <CAEhBLvg7ZUMja5zpFm2UQBXESW-0fL9L7EatR2aasstXd8ALHA@mail.gmail.com> <CABXB=RRvp0BLURq7M9iBb5anqaGsrvXeA1WmAroNji6bZP8p4w@mail.gmail.com> <5202C558.3010305@fjl.co.uk> <02C07E9F-ABB3-4A38-9638-21F913A08EC1@elde.net>
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On 08/08/2013 12:42, Terje Elde wrote: > On 8. aug. 2013, at 00:08, Frank Leonhardt <frank2@fjl.co.uk> wrote: >> As a suggestion, what happens if you read from the drives directly? Boot in single user and try reading a Gb or two using /bin/dd. It might eliminate or confirm a problem with ZFS. > If not too inconvenient, it'd be very interesting to see what'd happen if you were to physically disconnect (data and power) 5 of the 6 drives, then boot and dd from the remaining disk to /dev/null. Then repeat with another drive. > > You could boot from USB to leave the system itself otherwise untouched. > > The reason I'm suggesting is that I'm wondering if this can be down to a power or cable-issue, locking things up or causing retransmits, etc. > > Not sure if this would always be logged, others might be able to enlighten that issue. > > Terje > > And while you're at it, could you post the output of diskinfo -v /dev/[slices] - check the cylinder alignment and so on if you haven't already. Regards, Frank.
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