On 02/01/2013 17:49, Paul Mather wrote:
> Yesterday, I updated my RELENG_8 ZFS-only system that has worked like a champ
> for ages. After a successful install{kernel,world} and reboot, I noticed the
> 20121130 entry in /usr/src/UPDATING and upgraded my ZFS pool via "zfs upgrade
> -a". I also upgraded my boot blocks as requested, and as per the "ZFS notes"
> section of /usr/src/UPDATING.
>
> Unfortunately rebooting with the upgraded pool failed. The "windmill" boot
> spinner spins for a tiny amount of time and then stops dead. :-( I don't get
> to the boot loader menu at all.
>
> I downloaded a very recent RELENG_8 snapshot
> (FreeBSD-8.3-RELENG_8-r244923-JPSNAP-amd64-amd64-memstick.img) from
> pub.allbsd.org and was able to boot successfully from USB using that. I
> entered Fixit Mode and tried to write the boot blocks on the memstick image
> onto my hard drives but the resultant system still wouldn't boot. The
> commands I used (from Fixit Mode) are these:
>
> gpart bootcode -b /dist/boot/pmbr -p /dist/boot/gptzfsboot -i 1 ad4
> gpart bootcode -b /dist/boot/pmbr -p /dist/boot/gptzfsboot -i 1 ad6
>
> (ad4 and ad6 are my two hard drives.)
>
> If I "load zfs" before booting the USB memstick then I can see my old pool
> listed when I do "zfs import". I haven't tried importing the pool because
> I'm not sure if that would make the problem worse.
>
> Does anyone have any advice in restoring this system to bootability? I
> followed the standard "root on ZFS" recipe using a two drive mirror when
> installing the system initially. Each drive uses GPT with three partitions:
> freebsd-boot, freebsd-swap, and freebsd-zfs in that order. Like I said at
> the start, all this worked for a long time until just now when I upgraded the
> pool to enable "feature flags" support. :-(
>
> Any help is appreciated.
I think you may be running into problems with zpool.cache. This has
been fixed in current, which now has the ability to find the root zpool
without a valid zpool.cache, but that I suspect is faint comfort for you.
To recover from a toasted zpool.cache, you need to boot from alternate
media and then import your root zpool. It's easiest to do that to a
temporary directory. The important bit is to copy the zpool.cache onto
your actual zroot device:
-- Boot from install media to 'Live CD' and log in as root (no password)
# kldload zfs -- should load opensolaris.ko automatically
# cd /tmp -- this should be a writable MFS; you'll
need to arrange something similar if
not.
# zpool import -o cachefile=/tmp/zpool.cache -R /tmp/zroot zroot
-- this should create a zpool.cache file
# cp zpool.cache /tmp/zroot/boot/zfs/
# zfs umount -a
# shutdown -r
Eject the install media, and the system should boot up from your root zpool.
Cheers,
Matthew
--
Dr Matthew J Seaman MA, D.Phil.
PGP: http://www.infracaninophile.co.uk/pgpkey
JID: matt...@infracaninophile.co.uk
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