All my docker containers suddenly disappeared and noticed my cache drive was Unmountable: Unsupported or no file system. I have tried stopping the array and removing the cache drives (pool of 2) to start the array but then I get "Wrong Pool State Cache too many wrong or missing devices". I have attached diagnostics. I'm hitting a brick wall.

gamingnas-diagnostics-20251002-1102.zip

Removing a pool device will not fix filesystem issues, but if the array doesn't start, the pool is not set up/detected as a mirror. Reassign the pool device device and type

btrfs rescue zero-log /dev/sdr1

Then start the array and post new diags.

I just want to make sure I understand the steps.

1. Assign the pool devices back

2. Type "btrfs rescue zero-log /dev/sdr1" in the terminal

3. Start array

Is this right?

Yes, pool should be assigned as before; there shouldn't be any missing/new pool devices, all green icons.

Awesome, that got them recognized now. And my appdata is back since they lived on my cache drive. However, my docker containers are still gone, not sure what happened to them. I believe I should be able to recover those, forgetting how.

Attached diagnostics after starting the array.

gamingnas-diagnostics-20251002-1228.zip

I'm seeing I have two docker image files, caused by Unraid creating a new one when not finding the old one. I assume I should just delete the newly created one to fix this? Also, should I disable or enable the docker before I do this?

Edited October 2, 2025Oct 2 by kjclark23

Btrfs is detecting some data corruption; recommend scrubbing the pool.

Regarding the docker image, if there are two, delete the newer one; stop the Docker service first.

I disabled the docker and deleted the newer image file.

I ran the scrub and got this output

UUID:             6738fddc-e7e7-4acf-bf7a-c650d6ca514a
Scrub started:    Thu Oct  2 13:12:27 2025
Status:           finished
Duration:         0:07:09
Total to scrub:   455.63GiB
Rate:             1.03GiB/s
Error summary:    csum=8
  Corrected:      0
  Uncorrectable:  8
  Unverified:     0

I then went to enable the docker again and I get Docker Service failed to start.

Attached more diagnostics.

gamingnas-diagnostics-20251002-1325.zip

This file is corrupt; you need to delete or restore from a backup, then confirm the scrub finds 0 errors.

Oct 2 13:19:33 gamingNAS kernel: BTRFS error (device sdr1): unable to fixup (regular) error at logical 965458591744 on dev /dev/sdh1 physical 296395800576

Oct 2 13:19:33 gamingNAS kernel: BTRFS warning (device sdr1): checksum error at logical 965458591744 on dev /dev/sdh1, physical 296395800576, root 5, inode 15642614, offset 15794176, length 4096, links 1 (path: appdata/EmbyServer/transcoding-temp/656B96/656B96_689.ts)

Docker image is also corrupt; delete and recreate it, and if you keep getting more corruption, I recommend running memtest.

Many thanks. The scrub came back with no errors. Now I just need to restore my previous containers. Thanks for holding my hand!

All of a sudden my server crashed. I had to manually restart it and now my cahce drive is back to unmountable again. Ugh. I tried doing what you said before with "btrfs rescure..." but that resulted in "No valid Btrfs found on /dev/sdr1

ERROR: could not open ctree"

Posting diagnostics. Starting to worry I have a hardware problem.

gamingnas-diagnostics-20251005-2115.zip

Pool device changed IDs; try:

btrfs rescue zero-log /dev/sdq1

But even if it works again, and since it recurred, I would recommend backing up and reformatting the pool

Thank you! Back up again. I will backup and reformat it.