Date: Fri, 7 Dec 2012 17:22:40 +0100 From: Fabian Keil <freebsd-listen@fabiankeil.de> To: Matt Burke <mattblists@icritical.com> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS hang Message-ID: <20121207172240.037306e1@fabiankeil.de> In-Reply-To: <50C1DDE8.9030503@icritical.com> References: <50C1CB34.3000308@icritical.com> <50C1DDE8.9030503@icritical.com>
next in thread | previous in thread | raw e-mail | index | archive | help
[-- Attachment #1 --] Matt Burke <mattblists@icritical.com> wrote: > Obviously, the cause of my problems would seem to be a hosed disk. However > the kernel msgbuf shows no complaints from the drive before reboot. > > da8 is a 60GB OCZ Agility 3 SSD (purchased prior to realising just how > unreliable they are). According to the SMART data, it's had just 146GB of > reads and 278GB writes over 3 power cycles with only 3 months power on > time, similar to the others that have failed (~60% failure rate for ours) > > I can understand the drive failing, I just can't understand how it hung the > system. I have had a similar thing happen on one of these machines before > (with GENERIC and no dumpdev, so no debugging) with one of these disks on > an Areca HBA. In CURRENT, parts of the cam layer can silently hang under certain circumstances and this can negatively affect various other subsystems including ZFS: http://lists.freebsd.org/pipermail/freebsd-current/2012-October/037413.html I suppose this regression is old enough to have trickled down to the stable branches by now. I'm not saying that this is definitively the problem you are seeing, but I think it would explain the symptoms. > Could there be a problem with ATA devices on SCSI controllers which is > causing failures to be silently dropped? Is ZFS lacking a timeout on IO calls? I believe ZFS is designed with the expectation that timeouts are handled by the layers below it, so technically it doesn't "lack" the timeouts for IO calls ... Fabian [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlDCF9UACgkQBYqIVf93VJ0orQCfcmsNJbxWyacbww51lJTjO0aH c5wAn0l/fOn7P6yLYvr3Vp6+A4CvzQCB =fGcL -----END PGP SIGNATURE-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20121207172240.037306e1>