ZFS pool on FreeBSD 8.2-STABLE broken?

[Scot Hetzel]

On Mon, Mar 28, 2011 at 1:17 PM, Mark Morley <mark at islandnet.com> wrote:
> Hi there,
>
> I have a small backup server (8.2-STABLE).  It boots from ufs and has a zfs pool for backups that consists of 8 drives configured as 4 mirrored devices, totally around 2.5 TB.
>
> Been working great, no issues, until the past few days when remote rsyncs to it have started to get very slow (it's only at around %50 capacity).  Rebooting it helps for a while, then it gets slow again.  But this isn't the problem now...
>
> After the last reboot, it froze while booting right at the point where the file system gets mounted.  No errors, it just doesn't proceed past the ZFS version message.
>
> I rebooted single user and tried to access it with "zpool status", and the command hangs in the same way.  Any attempt to access it ("zfs list", for example) does the same thing.
>
> The disks themselves seem fine.  They are all connected to a pair of Adaptec RAID controllers (configured as individual drives, with mirroring handled by zfs) and the controller software shows them all to be intact.
>
> I disabled zfs in rc.conf and was able to boot, but I can't access the pool.
>
> Any ideas on how to diagnose and hopefully repair this?
>

Your going to need to download a recent -CURRENT ISO that contans zfs
v28, then you can try to recover the pool as outlined in this post
http://opensolaris.org/jive/message.jspa?messageID=445269

zpool import -nfF -R /mnt rpool

If it reports that it can get back to good pool state, then do actual
import with

zpool import -fF -R /mnt rpool

In case first command cannot rewind to older state, try to add -X option:

zpool import -nfFX -R /mnt rpool

and if it says that it can recover your pool with some data loss and you
are ok with it, then do actual import

zpool import -fFX -R /mnt rpool

Note: I haven't given this a try on my system yet, let me know how it goes ;-).

Scot