ZFS Accessing ZFS partition on USB stick

[balanga]

Had a problem upgrading a FreeNAS TrueNAS box yesterday which left the system unbootable, so I need to take a look at the boot device, ie a USB stick with a ZFS partition. I have no idea how to mount this. I've done a few searches but haven't yet come across instructions which work.
zpool import shows

   pool: freenas-boot
     id: 10549923701932750433
  state: ONLINE
status: Some supported features are not enabled on the pool.
action: The pool can be imported using its name or numeric identifier, though
    some features will not be available without an explicit 'zpool upgrade'.
config:

    freenas-boot  ONLINE
      da0p2       ONLINE

... but can't workout how to proceed from there...

 

[chungy]

Take a look at zpool-import(8)

 

[datasmurf]

zpool import -R /mnt freenas-boot where /mnt is the new mount point of the pool.

 

[Alain De Vos]

zpool import should work

 

[Cath O'Deray]

Need to avoid clobber.

Feature #6780: zfs(8) temporary mount point properties should include mountpoint - illumos gate - illumos reminds me:

• altroot …

 

[balanga]

Before starting this post I did a web search for the topic and did what was suggested...

zpool import and then zpool import -R /mnt freenas-boot:-

cannot import 'freenas-boot': pool was previously in use from another system.
Last accessed by <unknown> (hostid=0) at Mon May 24 22:10:44 2021
The pool can be imported, use 'zpool import -f' to import the pool.

zpool import -f /mnt freenas-boot

cannot import '/mnt': no such pool available

Does this mean my zfs partition is FUBAR?

 

[chungy]

You removed the -R.

 

[balanga]

zpool import -f -R /mnt freenas-boot

returns no message. mount does not show anything mounted and /mnt is empty

 

[covacat]

zfs list

 

[SirDice]

returns no message.

Good, that means it worked.

mount does not show anything mounted and /mnt is empty

An imported pool isn't automagically mounted, use zfs mount to mount what you need to access or zfs mount -a to blindly mount everything.

 

[Cath O'Deray]

returns no message.

You must export the pool before importing with the altroot.

If the prior import (without an altroot) caused clobber, be prepared for some difficulty.

Export, disconnect the drive then restart the OS.

 

[chungy]

In general, no output is good news in Unix.

Without -N, any file systems with canmount=on and mountpoints defined will automatically mount. If it's a root pool, it's often a good idea to use -N on import first because the OS root itself normally has canmount=noauto. And then there's mountpoint=legacy as a possibility that'll force you to use mount(8).