TrueNAS degraded pool due to unknown disk


I have a strange problem. My TrueNAS pool has 8 disks. They all show up and look fine. I did a SMART test on all of them and they passed successfully. My pool is degraded with the following status:

root@truenas[/dev/gptid]# zpool status Pool1
pool: Pool1
status: One or more devices could not be opened. Sufficient replicas exist for
the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using ‘zpool online’.
see: Message ID: ZFS-8000-2Q — OpenZFS documentation
scan: scrub repaired 0B in 06:58:19 with 0 errors on Sun Dec 17 01:36:43 2023

    NAME                                            STATE     READ WRITE CKSUM
    Pool1                                           DEGRADED     0     0     0
      raidz1-0                                      DEGRADED     0     0     0
        gptid/b470af02-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        gptid/b47c05d6-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        gptid/b499b444-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        gptid/0bf56f9e-2594-11ee-bb58-1c6f653f7f89  ONLINE       0     0     0
        gptid/b483569c-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        gptid/b4ae575d-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        4847501489953752832                         UNAVAIL      0     0     0  was /dev/gptid/b44abcb0-7867-11ed-b9ef-001b21b3bbe2
        gptid/b4a22fb0-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0
        gptid/b47595cc-7867-11ed-b9ef-001b21b3bbe2  ONLINE       0     0     0

errors: No known data errors

I can’t figure out who is the unknown disk, and what to do to fix the problem. Any help and guidance are very much appreciated.



From the UI, Storage > Disks it will list disks with their serial #

Thanks for the tip Pavlos, but the problem was that the faulty disk didn’t show up at all under Disks until I turned the system off, power down completely and rebooted. I was then able to see the failed disk serial number and take it offline, then replace it. The system is now resilvering and I expect my Pool to be online soon.

If you watch the drive activity lights long enough, you’ll see where all drives will flicker except the drive that is no longer part of the array. I’d say it is 90+% correct.

You might have just been able to offline/replace that drive without removing it, I’ve had that happen once and the drive lived on for another 5 years until I replaced the entire set to make things “bigger”.

Hi Greg,

I wish my enclosure was that good. I have an old desktop case with no light, no hot swap, but I like it, and for my home lab it’s good enough.

A question though, can I move all my disks, including my OS SSD, to a new enclosure and motherboard without losing my pool?