rescue the config

[temporal-agent]

i have a failed upgrade that won't finish booting.  i've tried to reinstall and import the config off the mirrored zfs array, but it can't seem to.  i can't seem to mount the zfs volume in another distro either.

is there any way to rescue the config?

[Patrick M. Hausen]

What does "zpool import" in that other distro say as a result?

[temporal-agent]

ubuntu 24.04:
failed to mount "zroot"
filesystem type zfs_member not configured in kernel

[Patrick M. Hausen]

Try FreeBSD 14.2.

Code Select Expand

zpool importto check if the pool is found.

Code Select Expand

zpool import -o altroot=/mnt zrootto perform the real import and not mount it over your live CD.

[temporal-agent]

FreeBSD was able to mount it, but i can't find it.

[Patrick M. Hausen]

/mnt is read-only in that live session it seems. Try e.g. "mkdir /mnt2" and use that instead. Or "mount -u orw /" before the entire "zpool dance". Something like that, I am not at my computer atm. The error message about "read-only" needs to go away, then you will find the data in /mnt/zroot.

[temporal-agent]

i mounted it in a temp folder, ls -lah says that there is nothing in zroot.

[Patrick M. Hausen]

What does "zfs list" say?

[astefanovski]

Apologies if it's not appropriate to reply to this thread, but it's one of the only ones that matches what I've been searching, and I thought if I find some resolution it can remain for anyone looking in the future. I woke up to OPNsense stuck on the first screen of booting, changing to last kernel did not help as it has once in the past.

I attempted to acess the zfs pool in a live CD of Ubuntu, but received the same kernel error as OP. I attempted to mount the zfs pool in a FreeBSD live CD, was unable to mount zroot/ROOT or zroot/ROOT/default, which google searches showed contain the config file. I thought maybe physical disk problems so I ran a L2 spinrite6.1 scan, which found no errors.

I put a different SSD in the machine and flashed 25.7 fresh, uploaded my last config backup I could find but it was before some extensive NAT/firewall/reverse proxy changes I'd rather not rebuild; I download config backups anytime I make big changes so I have no clue how the most recent backup I can find is from August, but here I am.

Contents of 'zfs list' are as follows:

Code Select Expand

NAME                        USED  AVAIL  REFER  MOUNTPOINT
zroot                      4.04G   213G  1.89M  /Volumes/OPNsense/zroot
zroot/ROOT                 3.55G   213G  1.95M  /Volumes/OPNsense
zroot/ROOT/20250401030029     8K   213G  1.73G  /Volumes/OPNsense
zroot/ROOT/default         3.55G   213G  1.82G  /Volumes/OPNsense
zroot/home                 1.99M   213G  1.99M  /Volumes/OPNsense/home
zroot/tmp                  15.7M   213G  15.7M  /Volumes/OPNsense/tmp
zroot/usr                  3.92M   213G    96K  /Volumes/OPNsense/usr
zroot/usr/ports            1.93M   213G  1.93M  /Volumes/OPNsense/usr/ports
zroot/usr/src              1.90M   213G  1.90M  /Volumes/OPNsense/usr/src
zroot/var                   411M   213G    96K  /Volumes/OPNsense/var
zroot/var/audit            1.93M   213G  1.93M  /Volumes/OPNsense/var/audit
zroot/var/crash            3.81M   213G  3.81M  /Volumes/OPNsense/var/crash
zroot/var/log               401M   213G   401M  /Volumes/OPNsense/var/log
zroot/var/mail             1.94M   213G  1.94M  /Volumes/OPNsense/var/mail
zroot/var/tmp              1.94M   213G  1.94M  /Volumes/OPNsense/var/tmp
I received no errors importing/mounting (on that attempt), tried a 'zpool scrub zroot,' with 'zpool status -v' as follows:

Code Select Expand

  pool: zroot
 state: ONLINE
  scan: scrub repaired 0B in 00:00:08 with 0 errors on Thu Oct  9 23:15:21 2025
config:

NAME        STATE     READ WRITE CKSUM
zroot       ONLINE       0     0     0
  disk4     ONLINE       0     0     0

errors: No known data errors
I'm at a loss for why zroot/ROOT (mounted: /Volumes/OPNsense/) is empty other than /home /tmp /usr /var /zroot subfolders, most of which have files in them.

'zfs list' is showing 3.55G in use in the dataset, would that be the case if someone gained access to my OPNsense machine and wiped out files but not directories in / ?

All the import errors I was getting initially were in the vein of 'permission denied' so I'm hoping there's some unresolved permissions issue going on where I need to 'take ownership' of the datasets or something along those lines? It's odd that the zroot mountpoint is a folder within /OPNsense alongside the files that should be in it, so maybe I need to import without mounting (-N) and then set mountpoints and mount one by one and make sure they're nested correctly?

I've run out of theories and realize I'm incredibly ignorant vis a vis ZFS, which I plan to work on as I intend to build a NAS in the future. I'm running as root (sudo -s) on the macOS terminal running openzfs via homebrew, installed today.

Any guidance would be appreciated, I am at a loss of hope and ideas.

[Patrick M. Hausen]

Unmount zroot/ROOT - your data is in zroot/ROOT/default. This is due to FreeBSD boot environments. The overlay mount of an empty directory hides the files.