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Date: Fri, 20 Mar 2009 15:30:11 +0000 (GMT)
From: "Mark Powell" <M.S.Powell@salford.ac.uk>
To: Mark Powell <M.S.Powell@salford.ac.uk>
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Cc: kevin <kevinxlinuz@163.com>, FreeBSD Current <freebsd-current@freebsd.org>,
	Daniel Eriksson <daniel@toomuchdata.com>
Subject: Re: Apparently spurious ZFS CRC errors (was Re: ZFS data error
 without reasons)
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On Fri, 20 Mar 2009, Mark Powell wrote:

>  As this same hardware worked, well with 7 for a long time, and can work 
> perfectly with 8 for several days until the errors strike, this seems like 
> some curious 8 problem?

Hmmm. Perhaps I'm not being fair on 8. Just had a look at my loader.conf 
for 7 and I can see that I used to run with every zfs*disable on. I've 
just rebooted 8 with:

vfs.zfs.cache_flush_disable: 1
vfs.zfs.mdcomp_disable: 1
vfs.zfs.prefetch_disable: 1
vfs.zfs.zil_disable: 1
hw.ata.wc: 1

The current fs which produced errors on every scrub now reports no errors.
   I now need to find which option fixed it.
   I suspect hw.ata.wc. Is this still a known issue?
   Cheers.

-- 
Mark Powell - UNIX System Administrator - The University of Salford
Information & Learning Services, Clifford Whitworth Building,
Salford University, Manchester, M5 4WT, UK.
Tel: +44 161 295 6843  Fax: +44 161 295 5888  www.pgp.com for PGP key