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Date: Mon, 9 Nov 2009 10:12:55 +0100
From: Gerrit =?ISO-8859-1?Q?K=FChn?= <gerrit@pmp.uni-hannover.de>
To: "James R. Van Artsdalen" <james-freebsd-fs2@jrv.org>
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Cc: freebsd-fs@freebsd.org
Subject: Re: trace for zfs panic mounting fs after crash with RC2
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On Fri, 06 Nov 2009 17:02:23 -0600 "James R. Van Artsdalen"
<james-freebsd-fs2@jrv.org> wrote about Re: trace for zfs panic mounting
fs after crash with RC2:

JRVA> How the ZIL got corrupted - if it did - is a harder question.

I think it is. Otherwise zfs would not crash while trying to replay the
ZIL, wouldn't it?
It seems that this happens rather easily with the system I have at hand
(it happend twice to me so far - and I crashed the system only twice,
that makes 100%, although I doubt that it is that reproducible). Searching
around I found some reports of the same or similar issues (but no
solution). So apart from recovering my fs (I did not try your suggested
patch yet), there are two things I regard as very important:

1. Find you why the ZIL gets corrupted under some circumstances.
2. Find a safe way to recover a fs with a corrupted ZIL.

I guess I could live with a corrupted ZIL after a crash, if there was some
kind of --ignore-zil switch to get my data back online. In any case, zfs
should not panic on corrupted ZIL data, should it?

As I do not dare to use the system for storing data until this is sorted
out, I can try out almost anything to get more information about the
problem. Please let me know what I should do to support debugging.


cu
  Gerrit