Date: Mon, 5 Nov 2007 12:05:08 -0500 From: Adam McDougall <mcdouga9@egr.msu.edu> To: Kris Kennaway <kris@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: ZFS Hangs Message-ID: <20071105170508.GA4037@egr.msu.edu> In-Reply-To: <472EE13E.9030908@FreeBSD.org> References: <200711021208.25913.Thomas.Sparrevohn@btinternet.com> <200711041423.54336.Thomas.Sparrevohn@btinternet.com> <472DDEA2.7080804@FreeBSD.org> <200711050041.38229.Thomas.Sparrevohn@btinternet.com> <472EE13E.9030908@FreeBSD.org>
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On Mon, Nov 05, 2007 at 10:24:14AM +0100, Kris Kennaway wrote: Thomas Sparrevohn wrote: >> On Sunday 04 November 2007 15:00:50 Kris Kennaway wrote: >>> http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html >>> >> Oh my god - Overlooked that ;-) - funny that - Its a bit tricky as it not >> possibly to dump a kernel >> when the swap is on ZFS - I did a test with all debugging enabled and the >> problem >> did not show up - which makes it somewhat nasty - I check if I can >> reproduce it with only DDB enabled You can still hook up a serial console, or at the very least take photographs of the screen with the relevant DDB information. Or add another disk and dump on that. Kris I have some screenshots of ps in ddb from one of several zfs hangs I've had on one amd64 system: http://www.egr.msu.edu/~mcdouga9/pics/zfs/ I didn't post every single screenful since I don't have a microsd reader handy, and emailing the pictures off my phone is painful. If I missed a screenshot of one or more particular processes that might have a telling state, let me know. I also have a gzipped kernel + dump from a forced panic when it was in this state, if a developer is interested in it please let me know so I can post it somewhere private since the system is in NIS and likely has tables cached in memory. It is running a kernel from Oct 17. I tried a kernel with WITNESS, INVARIANTS etc but it did the same hang without any panic. I completed a zpool scrub this morning with no errors. Lately zfs seems to wedge up every single night when rsync from remote servers run. This is the only amd64 system I have zfs on, the other two are i386 and the problems on those systems have only been kmem panics which so far have been avoidable. I can help by checking somewhat specific things and running prescribed tests, but right now I don't have time to tackle this problem on this system and learn how to debug it entirely on my own starting with nothing more than a DDB guide from the handbook. Its not that I refuse to; I recognize its difficult to join remote skill with local hands for something this technical. Friday I replaced the motherboard/cpu just as a shot in the dark (since the system had some strange instability in the past) but this didn't help zfs (not surprised). When zfs was hung saturday morning, I tried to reboot it but reboot would not even get far enough to stop new ssh connections.
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