I think I might have accidentally killed my cache array, which is incredibly frustrating.
For some background, my server has 2x1TB NVMe drives in the cache array (set in a RAID1 config so that the entire 2TB can be used). 3xxGB were being used. I'm about to setup a second unraid server and wanted to take 1 of the 2 drives over to the new machine. I looked up the instructions here and people said:
- Shut down the array
- Remove the drive you want to remove
- Start the array
All this did was make it fail to mount the cache. There were no progress bars or warnings about any activity happening otherwise. I then panicked and shut the array down again and put the 2nd drive back into the cache pool. Same thing, same error: "unmountable: no filesystem".
When I do a btrfs fi show on the drive label, this is the output:
warning, device 2 is missing
Label: none uuid: f46e54ec-68b4-48d9-94c5-3b9039d0b25a
Total devices 2 FS bytes used 373.74GiB
devid 1 size 931.51GiB used 204.03GiB path /dev/nvme0n1p1
*** Some devices missing
What troubles me here is that the used on disk 1 clearly doesn't match the used on the entire file system, which would tell me that now the entirety of my cache array is destroyed and unrecoverable.
What did I do wrong and is there anything I can do to restore any amount of files?