I was moving my server and had an accidental unclean shutdown (psu came unplugged during start) and my nvme cache drive is giving the error "Unmountable: unsupported or no file system".

I tried shutting down the array, unassigning the drive, removing the cache pool, restart the array, shut down and rebuild the cache pool with the drive reassigned with no luck (the same error persists).

I also tried updating from 7.0.0 to 7.1.4 with no success either

Diagnostics attached - any other things I could try before I break down to reformatting or how I can at least mount to transfer the files off the nvme drive?

tower-diagnostics-20251005-1110.zip

Post the output from zpool import

pool: cache

id: 12848514097395679192

state: ONLINE

status: Some supported features are not enabled on the pool.

(Note that they may be intentionally disabled if the

'compatibility' property is set.)

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:

cache ONLINE

nvme1n1p1 ONLINE

sdc1 ONLINE

nvme0n1p1 ONLINE

And now zpool import cache

I'm not able to view any of the pools now with zpool import - outputs below and updated diagnostics file if that helps. I also tried stopping and restarting the array with pool removal and no change to the zpool commands.

root@Tower:~# zpool import

no pools available to import

root@Tower:~# zpool import cache

cannot import 'cache': a pool with that name already exists

use the form 'zpool import <pool | id> <newpool>' to give it a new name

tower-diagnostics-20251006-1900.zip

Edited October 7, 2025Oct 7 by lgr

There's already a pool named cache imported.

  pool: cache
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
	The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
	the pool may no longer be accessible by software that does not support
	the features. See zpool-features(7) for details.
config:
	NAME         STATE     READ WRITE CKSUM
	cache        ONLINE       0     0     0
	  nvme1n1p1  ONLINE       0     0     0
	  sdc1       ONLINE       0     0     0
	  nvme0n1p1  ONLINE       0     0     0
errors: No known data errors

And nvem1n1 is part of it.

Yeah, my cache pool still appears to be in the same configuration and showing the same unmountable error as my original post. Is there something I’m missing that should have resolved the issue?

You cannot have a single device from another pool mount by itself, if there's data there, you should be able to import that 3 device pool using the GUI, but it must be exported first.

In the gui dsc1 and nvme0n1p1 are set as unassigned to any pool. Are you suggesting I add these two devices to my cache pool via the gui?

And for exporting I would just do "zpool export cache" before modifying the drives in the cache pool on the gui?

51 minutes ago, lgr said:

Are you suggesting I add these two devices to my cache pool via the gui?

Not add, reimport the pool with the 3 devices.

First export the pool with zpool export cache, then stop the array and

on main click on the first device for that pool and then "remove pool"

back on main, create a new pool with the same name and 3 slots

assign the 3 pool devices, leave the filesystem set to auto

start the array to import the pool and post new diags

Looks like I am unable to export the cache pool now since it's busy. I disabled docker and VM's and there doesn't appear to be any file activity on the pool looking on the file activity plugin.

root@Tower:~# zpool export cache

cannot export 'cache': pool is busy

That means something us using the pool, if you can't find what is using it reboot it. It should not be imported automatically unless you have something custom doing it.

Looks like adding all three drives solved it and I can mount successfully. Thanks for the patience and help!