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Date:      Thu, 8 Aug 2013 13:42:38 +0200
From:      Terje Elde <terje@elde.net>
To:        Frank Leonhardt <frank2@fjl.co.uk>
Cc:        "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org>
Subject:   Re: Terrible disk performance with LSI / FreeBSD 9.2-RC1
Message-ID:  <02C07E9F-ABB3-4A38-9638-21F913A08EC1@elde.net>
In-Reply-To: <5202C558.3010305@fjl.co.uk>
References:  <CABXB=RSRnB41yjq5Qcbiz-JCRssNwx2AatJ2Dn+HhuD9GaBh+w@mail.gmail.com> <CAEhBLvg7ZUMja5zpFm2UQBXESW-0fL9L7EatR2aasstXd8ALHA@mail.gmail.com> <CABXB=RRvp0BLURq7M9iBb5anqaGsrvXeA1WmAroNji6bZP8p4w@mail.gmail.com> <5202C558.3010305@fjl.co.uk>

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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 i=
n single user and try reading a Gb or two using /bin/dd. It might eliminate o=
r confirm a problem with ZFS.

If not too inconvenient, it'd be very interesting to see what'd happen if yo=
u were to physically disconnect (data and power) 5 of the 6 drives, then boo=
t and dd from the remaining disk to /dev/null. Then repeat with another driv=
e.=20

You could boot from USB to leave the system itself otherwise untouched.=20

The reason I'm suggesting is that I'm wondering if this can be down to a pow=
er or cable-issue, locking things up or causing retransmits, etc.=20

Not sure if this would always be logged, others might be able to enlighten t=
hat issue.=20

Terje





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