From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Lord <liml@rtr.ca>
Subject: Re: MD/RAID time out writing superblock
Date: Thu, 17 Sep 2009 12:17:19 -0400
Message-ID: <4AB2610F.8010904@rtr.ca>
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To: Chris Webb <chris@arachsys.com>
Cc: Tejun Heo <teheo@suse.de>, linux-scsi@vger.kernel.org, Ric Wheeler <rwheeler@redhat.com>, Andrei Tanas <andrei@tanas.ca>, NeilBrown <neilb@suse.de>, linux-kernel@vger.kernel.org, IDE/ATA development list <linux-ide@vger.kernel.org>, Jeff Garzik <jgarzik@redhat.com>, Mark Lord <mlord@pobox.com>
List-Id: linux-ide@vger.kernel.org

Mark Lord wrote:
> Tejun Heo wrote:
>> Hello,
>>
>> Mark Lord wrote:
>>> Tejun.. do we do a FLUSH CACHE before issuing a non-NCQ command ?
>>
>> Nope.
>>
>>> If not, then I think we may need to add code to do it.
>>
>> Hmm... can you explain a bit more?  That seems rather extreme to me.
> ..
> 
> You may recall that I first raised this issue about a year ago,
> when my own RAID0 array (MythTV box) started showing errors very
> similar to what Chris is reporting.
> 
> These were easily triggered by running hddtemp once every few seconds
> to log drive temperatures during Myth recording sessions.
> 
> hddtemp uses SMART commands.
> 
> The actual errors in the logs were command timeouts,
> but at this point I no longer remember which opcode was
> actually timing out.  Disabling the onboard write cache
> immediately "cured" the problem, at the expense of MUCH
> slower I/O times.
..

Speaking of which.. 

Chris:  I wonder if the errors will also vanish in your situation
by disabling the onboard write-caches in the drives ?

Eg.  hdparm -W0 /dev/sd?