Date: Mon, 9 Apr 2012 11:50:39 -0700 From: Rumen Telbizov <telbizov@gmail.com> To: freebsd-stable@freebsd.org Subject: ZFS: can't read MOS Message-ID: <CAENR%2B_X6gb5TB01i3FTfq_zD=RyFUGfLAWwA56SNm6Gqf_49iw@mail.gmail.com>
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Hello everyone,
I have a ZFS FreeBSD 8.2-STABLE (Aug 30, 2011) that I am having issues with
and might use some help.
In a nutshell, this machine has been running fine for about a year and a
half but after a recent power
outage (complete colo blackout) I can't boot of the ZFS pool any more.
Here's the error I get (attached screenshot as well):
ZFS: i/o error - all block copies unavailable
ZFS: can't read MOS
ZFS: unexpected object set type 0
ZFS: unexpected object set type 0
FreeBSD/x86 boot
Default: zroot:/boot/kernel/kernel
boot: ZFS: unexpected object set type 0
I've been searching the net high and low for an actual solution but all the
threads end up nowhere.
I hope I can get some clue here. Thanks in advance.
Here's the relevant hardware configuration of this box (serves as a backup
box).
- SuperMicro 4U + another 4U totalling 48 x 2TB disks
- Hardware raid LSI 9261-8i holding both shelves giving 1 mfid0 device
to the OS
- Hardware raid 60 -- 6 x 8 raid6 groups
- ZFS with gptzfsboot installed on the "single" mfid0 device. Partition
table is:
[root@mfsbsd /zroot/etc]# gpart show -l
=> 34 140554616765 mfid0 GPT (65T)
34 128 1 (null) (64k)
162 33554432 2 swap (16G)
33554594 140521062205 3 zroot (65T)
- boot device is: vfs.root.mountfrom="zfs:zroot" (as per loader.conf)
- zpool status is:
[root@mfsbsd /zroot/etc]# zpool status
pool: zroot
state: ONLINE
scan: scrub canceled on Mon Apr 9 09:48:14 2012
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
mfid0p3 ONLINE 0 0 0
errors: No known data errors
- zpool get all:
[root@mfsbsd /zroot/etc]# zpool get all zroot
NAME PROPERTY VALUE SOURCE
zroot size 65T -
zroot capacity 36% -
zroot altroot - default
zroot health ONLINE -
zroot guid 3339338746696340707 default
zroot version 28 default
*zroot bootfs zroot local*
zroot delegation on default
zroot autoreplace off default
zroot cachefile - default
zroot failmode wait default
zroot listsnapshots on local
zroot autoexpand off default
zroot dedupditto 0 default
zroot dedupratio 1.00x -
zroot free 41.2T -
zroot allocated 23.8T -
zroot readonly off -
Here's what happened chronologically:
- Savvis Toronto blacked out completely for 31 minutes
- After power was restored this machine came up with the above error
- I managed to PXE boot into mfsbsd successfully and managed to import
the pool and access actual data/snapshots - no problem
- Shortly after another reboot the hardware raid controller complained
that it has lost
it's configuration and now sees only half of the disks as foreign good
and the
rest as foreign bad. BIOS didn't see any boot device.
- Spent some time on the phone with LSI and managed to restore the
hardware RAID
by basically removing any and all configuration, making disks
unconfigured good
and recreating the array in exactly the same way as I created it in the
beginning BUT
with the important exception that I did NOT initialize the array.
- After this I was back to square one where I could see all the data
without any loss
(via mfsbsd) but cannot boot of the volume any more.
- First thing I tried was to restore the boot loader without any luck:
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 mfid0p1
- Then out of desperation, took zfsboot, zfsloader, gptzfsboot from
9.0-RELEASE and replaced them in /boot,
reinitialized again - no luck
- Currently running zdb -ccv zroot to check for any corruptions - I am
afraid this will take forever since I have *23.8T* used space. No errors
yet
- One thing I did notice is that zdb zroot returned the metaslab
information line by line very slowly (10-15 seconds a line). I don't know
if it's related.
- Another thing I tried (saw that in a thread) without any difference
whatsoever was:
# cd src/sys/boot/i386/zfsboot
# make clean; make cleandir
# make obj ; make depend ; make
# cd i386/loader
# make install
# cd /usr/src/sys/boot/i386/zfsboot
# make install
# sysctl kern.geom.debugflags=16
# dd if=/boot/zfsboot of=/dev/da0 count=1
# dd if=/boot/zfsboot of=/dev/da0 skip=1 seek=1024
# reboot
At this point I am contemplating how to evacuate all the data from there or
better yet put some USB flash to boot from.
I could provide further details/execute commands if needed. Any help would
be appreciated.
Thank you,
--
Rumen Telbizov
http://telbizov.com
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