I had 2 ZFS disks in a mirrored pool. I removed the pool and then tried to mount one of the disks in an array. Unfortunately, it gives me an error message that the disk is unmountable. I then tried to mount it again as ZFS pool, but this also gives me the same error.

Any idea whether I can get the content back? Attached diagnostic file. Thanks!

tower-diagnostics-20260201-1526.zip

Post the output from zpool import

Shall I create a zfs pool again and then post this log? At current stage, it’s removed. Shall I recreate it with both disks? Does the order matter?

For now

1 hour ago, JorgeB said:

Post the output from zpool import

Thanks, here we go: no pools available to import

And zpool status

pool: disk1

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.

scan: resilvered 15.0T in 1 days 08:07:46 with 0 errors on Fri Jan 16 18:10:47 2026

config:

NAME STATE READ WRITE CKSUM

disk1 ONLINE 0 0 0

mirror-0 ONLINE 0 0 0

sdb1 ONLINE 0 0 0

sdc1 ONLINE 0 0 0

errors: No known data errors

The pool is already imported, with the array stopped, that won't work.

To return to a correct config, first export the pool with zpool export disk1

Then reimport it in a two-device pool:

on main create a new pool with the name you want and 2 slots

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

start the array to import the pool

Assuming the pool mounts correctly after that, and it should, if you still want to break up the mirror:

stop array

unassign one of the pool devices

start array

That will transform the remaining device into a single device pool. You can then assign the other device to the array, etc., and format it.

A bit worried about data loss, so let me double-check with you that I am doing the right steps.

Terminology: This Unraid does not have an Unraid Array. I tried to create one with one of the ZFS disks from the ZFS pool, but this did not work.

I would now "stop array" (currently enabled for another pool). Then on command line, I'd run "zpool export disk1". Then I add a new ZFS pool. To this pool. I add both of my ZFS disks (order does not matter). And then hopefully my data is back.

Is this right?

20 hours ago, steve1977 said:

I would now "stop array" (currently enabled for another pool). Then on command line, I'd run "zpool export disk1". Then I add a new ZFS pool. To this pool. I add both of my ZFS disks (order does not matter). And then hopefully my data is back.

Correct

All worked out well, thank you