I really screwed this up. I was trying to replace my cache drive with a larger one. I only have the one. I guess I didn't really understand the process. I stopped the array, changed the cache to 2 drives, and added the other. I guess it copied everything after a while. I checked both drives in the terminal and they both had the same amount of information. Turn out the new one (old one really) was too old and I didn't like the smart report so I replaced it. I thought I could just remove the smaller one from the pool and put it back down to one but now I can't get the cache drive back online. I just tried a few combinations of things, even putting it back how it was, but with just one drive it says it has no filesystem. I did not check the box and format so I don't know why it would say that. I thought maybe I could mount one in unassigned devices and copy it over but it won't mount in UD. I'm not sure what to do. Any ideas? At the very least, can I back it up somehow?

Please post the diagnostics: Tools -> Diagnostics

Should have done that to begin with. Sorry.

tower-diagnostics-20200216-0438.zip

Diags are after rebooting so can't see what happened, but no valid btrfs filesystems are being detected which suggest one or both devices were wiped, still try these options, on both disks.

Well, this isn't good. I tried all those options. None of them worked. They all basically said no BTRFS system found. The restore command restored 2 files though. Not the ones I need unfortunately. I'm really unsure of what I did but I did not format anything.

Actually, I did managed to get the restore command working but I don't think it worked very well. there were lots of errors. The main file I was concerned about was a VM image. It restored it but it's 232gb with only about 500MB on disk.

Edited February 16, 20206 yr by bobbintb

Well, I checked and everything was backed up so I just decided to format and restore.

Yep, because it looked like the superblock was wiped wasn't very hopeful btrfs recovery options would work well, possibly only option would be some deleted file recovery util.