Date: Tue, 8 May 2012 12:48:49 -0700 From: Freddie Cash <fjwcash@gmail.com> To: FreeBSD Filesystems <freebsd-fs@freebsd.org> Subject: Re: Broken ZFS filesystem Message-ID: <CAOjFWZ4yvv3ffRXBKQec%2BnCjKfoWo6z2K8n%2BARFKdaTgF62z_Q@mail.gmail.com> In-Reply-To: <CAOjFWZ5OVG-ByhS_NDkF2-gbjUivGBxqLZZQaqMuLS-Q5ivDqA@mail.gmail.com> References: <CAOjFWZ5OVG-ByhS_NDkF2-gbjUivGBxqLZZQaqMuLS-Q5ivDqA@mail.gmail.com>
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On Tue, May 8, 2012 at 10:23 AM, Freddie Cash <fjwcash@gmail.com> wrote: > I have an interesting issue with one single ZFS filesystem in a pool. > All the other filesystems are fine, and can be mounted, snapshoted, > destroyed, etc. =C2=A0But this one filesystem, if I try to do any operati= on > on it (zfs mount, zfs snapshot, zfs destroy, zfs set <anything>), it > spins the system until all RAM is used up (wired), and then hangs the > box. =C2=A0The zfs process sits in tx -> tx_sync_done_cv state until the > box locks up. =C2=A0CTRL+T of the process only ever shows this: > =C2=A0 =C2=A0load: 0.46 =C2=A0cmd: zfs 3115 [tx->tx_sync_done_cv)] 36.63r= 0.00u 0.00s 0% 2440k > > Anyone come across anything similar? =C2=A0And found a way to fix it, or = to > destroy the filesystem? =C2=A0Any suggestions on how to go about debuggin= g > this? =C2=A0Any magical zdb commands to use? > > The filesystem only has 5 MB of data in it (log files), compressed via > LZJB for a compressratio of ~6x. =C2=A0There are no snapshots for this > filesystem. > > Dedupe is enabled on the pool and all filesystems. After more fiddling, testing, and experimenting, it all came down to not enough RAM in the box to mount the 5 MB filesystem. After installing an extra 8 GB of RAM (32 GB total), everything mounted correctly. Took 27 GB of wired kernel memory (guessing ARC space) to do it. Unmount, mount, export, import, change properties all completed successfully. And the box is running correctly with 24 GB of RAM again. We'll be ordering more RAM for our ZFS boxes, now. :) --=20 Freddie Cash fjwcash@gmail.com
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