So I am a long-time Windows users doing my damnest to rid myself of windows.. I created an Unraid server about a year ago replacing primarily a media sharing server but have expanded my server with Apps/Dockers etc. My media pool was a JBOD collection of 4 drives in BTRFS format. No parity as its mostly downloaded content that I'm not particularly worried about. I recently had one of my 4 drives die but it has taken down my whole drivepool and I am not sure what to do to get this back up and running with the 3 good drives.
The Drivepool shows as "Unmountable: wrong or no file system"
I removed the dead drive which shows up as an unassigned Disk in an attempt to shrink my pool to the 3 good drives but I am still unsuccessful in seeing the pool.

What do I need to get the back up.

See attached image from my Main page.

Attach Diagnostics ZIP to your NEXT post in this thread.

Gotcha... Thank you!

Diagnostics attached.

Cheers!

userver-diagnostics-20251228-0747.zip

17 hours ago, WinoOutWest said:

My media pool was a JBOD collection of 4 drives in BTRFS format.

If the pool was made of 4 BTRFS drives without redundancy, it won't mount with a device missing; it requires all 4.

Post the output from btrfs fi show

I believe I had tried to shrink the array following some youtube video to remove the dead drive. (this happened just before Christmas so I had to leave for a bit)

Here is my output:

root@UServer:~# btrfs fi show

Label: none uuid: fd9e1409-aac6-4a15-a19d-1c566f0d5c22

Total devices 1 FS bytes used 144.00KiB

devid 1 size 7.28TiB used 2.02GiB path /dev/sdc1

Label: none uuid: 581e667e-0743-4d89-88d2-91083c8d1b54

Total devices 1 FS bytes used 2.52GiB

devid 1 size 40.00GiB used 5.52GiB path /dev/loop2

Label: none uuid: 71b52138-4a5c-4dc4-ab7a-378a071403d0

Total devices 1 FS bytes used 1.14MiB

devid 1 size 1.00GiB used 126.38MiB path /dev/loop3

Label: none uuid: 3d227956-f60f-45f7-b34c-4ae49a8fde72

Total devices 4 FS bytes used 34.45TiB

devid 1 size 20.01TiB used 16.48TiB path /dev/sda1

devid 2 size 16.37TiB used 7.84TiB path /dev/sdd1

devid 3 size 14.55TiB used 6.02TiB path /dev/sdb1

devid 4 size 12.73TiB used 4.20TiB path /dev/sde1

27 minutes ago, WinoOutWest said:

Total devices 4 FS bytes used 34.45TiB

devid 1 size 20.01TiB used 16.48TiB path /dev/sda1

devid 2 size 16.37TiB used 7.84TiB path /dev/sdd1

devid 3 size 14.55TiB used 6.02TiB path /dev/sdb1

devid 4 size 12.73TiB used 4.20TiB path /dev/sde1

All pool devices are present, sde is unassigned and has a lot of UDMA CRC errors, suggesting a bad SATA cable. Suggest replacing it then:

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 4 slots

assign all 4 pool devices, leave the filesystem set to auto

start the array to import the pool and post new diags.

WOW!

Followed your advice and the pool came up just fine and seems to be intact.

Thank you so much!!

I've attached my diags again so now I have 2 questions.

Drive 4 is a 14TB drive that was giving me the errors. I was planning on removing this as I thought it was bad. Do you think I still need to replace it?

Also - I bought a new 22tb drive with the thought of re-creating this pool with parity. Can I easily do that? I was going to punt the 14TB as part of that but suppose I could leave it in there if its still healthy.

Again - your help is much appreciated!!
Cheers!
Darren

userver-diagnostics-20251229-0957.zip

SMART for that drive looks fine, only issue is the UDMA CRC errors, but that's typically a bad SATA cable, and probably what was causing the issues with it.

The current pool has no redundancy, meaning if you lose a drive you lose the pool.

You could add a new device and then rebalance the pool to raid5, but btrfs raid5 is still considered experimental and not really recommended for production.

My recommendation would be to create an array with parity or a raidz zfs pool.

The array option, while slower than a zfs pool, would likely be easier to create, assuming you cannot create a full pool backup, e.g., add the new 22TB drive as disk1, no parity for now, move all the data you can from the pool to that disk, remove one of the smaller disks from the pool (this would need to be done manually using the CLI, but I can post instructions if you want), and then add that removed disk to the array, keeping repeating with the other smaller disks until you have all the data moved, in the end, move the other 22TB drive to the parity slot to protect the array.

Oh, and don't forget to replace that SATA cable for disk 4.