Date: Wed, 11 Jan 2012 23:12:35 +0530 From: Gautam Mani <gautam@execve.net> To: Yamagi Burmeister <lists@yamagi.org>, mckusick@mckusick.com Cc: freebsd-current@freebsd.org, bryce@bryce.net Subject: Re: FS hang when creating snapshots on a UFS SU+J setup Message-ID: <20120111225754.GAf9c67.linbox@execve.net> In-Reply-To: <20120111103039.d342aef4.lists@yamagi.org> References: <20120109183051.1e4de3ca.lists@yamagi.org> <201201101830.q0AIUDP7062707@chez.mckusick.com> <20120111103039.d342aef4.lists@yamagi.org>
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On Wed, Jan 11, 2012 at 10:30:39AM +0100, Yamagi Burmeister wrote: > Hello, > I've done some tests to verify that the problem only occures when SU+J > is used, but not SU without J. In fact, I did run the following two > loops on different TTYs in parallel: I also confirm this using a similar technique. The panic is only seen with SU+J and not with just SU. I did a similar cp -R /root /var/tmp ; rm -rf /var/tmp/root and the panic was trigger with dump -0L... I got the panic (again in less than a minute of issuing the dump command) -- I also got the "giving up on dirty" kind of message. I took a picture of the screen -- I am not sure if that helps! http://picpaste.com/11012012519-LF0sWlpw.jpg > Since it's much more likely that the problems described above arrise > when the the filesystem is loaded (for example by the first loop) while > taking the snapshot this looks like some kind of race condition or > something like that. > Earlier I have seen this happen with dump without any high load -- or atleast very minimum -- again with the /var because some logs were written or cronjob was running writing to it. That didnt panic as I indicated in my previous email -- hogged the CPU and forced a power-cycle. Do let me know if I can try something further. Thanks Gautam
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