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Date: Sun, 11 Nov 2012 10:12:58 +0200
From: Andriy Gapon <avg@FreeBSD.org>
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To: Peter Jeremy <peter@rulingia.com>
Subject: Re: zfs diff deadlock
References: <20121110223249.GB506@server.rulingia.com>
 <20121111072739.GA4814@server.rulingia.com>
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on 11/11/2012 09:27 Peter Jeremy said the following:
> On 2012-Nov-11 09:32:49 +1100, Peter Jeremy <peter@server.rulingia.com>
> wrote:
>> I recently decided to do a "zfs diff" between two snapshots to try and
>> identify why there was so much "USED" space in the snapshot. The diff ran
>> for a while (though with very little IO) but has now wedged unkillably.
>> There's nothing on the console or in any logs, the pool reports no
>> problems and there are no other visible FS issues.  Any ideas on tracking
>> this down?
> ...
>> The systems is running a 4-month old 8-stable (r237444)
> 
> I've tried a second system running the same world with the same result, so 
> this looks like a real bug in ZFS rather than a system glitch.
> 

Are you able to catch the state of all threads in the system?
E.g. via procstat -k -a.
Or a crash dump.

-- 
Andriy Gapon