Date: Tue, 10 Nov 2009 16:46:22 +0100 From: Gerrit =?ISO-8859-1?Q?K=FChn?= <gerrit@pmp.uni-hannover.de> To: Graham Todd <gtodd@bellanet.org> Cc: freebsd-fs@freebsd.org Subject: Re: trace for zfs panic mounting fs after crash with RC2 Message-ID: <20091110164622.6bc7aca1.gerrit@pmp.uni-hannover.de> In-Reply-To: <4AF98032.9050808@bellanet.org> References: <20091106094734.4b056899.gerrit@pmp.uni-hannover.de> <4AF4123A.4080301@andric.com> <20091106231440.4f0f2cbb.gerrit@pmp.uni-hannover.de> <4AF4AAFF.2080104@jrv.org> <20091109101255.e81774e4.gerrit@pmp.uni-hannover.de> <4AF98032.9050808@bellanet.org>
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On Tue, 10 Nov 2009 10:01:06 -0500 Graham Todd <gtodd@bellanet.org> wrote about Re: trace for zfs panic mounting fs after crash with RC2: GT> > I guess I could live with a corrupted ZIL after a crash, if there GT> > was some kind of --ignore-zil switch to get my data back online. In GT> > any case, zfs should not panic on corrupted ZIL data, should it? GT> GT> Is there is a way to "manually" use zdb to mimic the "zpool clear" GT> command introduced in OpenSolaris's ZFS with PSARC-2009479? GT> GT> http://www.c0t0d0s0.org/archives/6067-PSARC-2009479-zpool-recovery-a.html FYI: Meanwhile I opened a PR for the issue (kern/140433) and got some request for additional zdb input (that I will hopefully be able to provide later this evening). The page above looks interesting, though. There it is mentioned (in the comments) that you can achieve the same thing zpool clear does... but it is not mentioned how. Does anyone here know? GT> I have no idea if this would help: in fact it might very well be GT> dangerous for the pool that Gerrit is trying to recover. Are you able GT> to copy the pool somehow before trying experiments? I do not care that much about this specific pool, since I only installed the system and some software. But I want to know I can handle this situation before I put data on the disks. :-) GT> I think the current state of "disaster recovery" tools and methods for GT> ZFS makes some folks nervous. With so much error checking "built in" GT> there's fewer tried and true "old school" sysadmin approaches to GT> recovering lost data after the fact. As long as these situations do not happen, it's ok for me to have no way to recover. :-) I am using zfs since Pawel made the first patchset available in autumn 2006 and never had to face a situation like this so far. As it happend two times in a row now on this new machine, I guess it must have something to do with the hardware. OTOH, everything seems to run fine, unless the machine crashes and corrupts the zil in some strange way. GT> So thanks for debugging your GT> problem in public. I hope you can resolve things and document how you GT> did it for everyone. I hope we get this resolved, too. As long as I do not have to fear to loose important data, I can do almost anything with the machine for debugging. cu Gerrit
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