I have a disk that used to have data on it that says "Unmountable: No file system".  I looked at the folder in the share settings and there is no files saved to this disk, so I'm like where did they go?

 

Here's what happened.  (20 data disks, 1 cache, 2 parity)

- Removed disk 12 (3tb with smart errors), replaced with new disk (4tb).

- At the end of rebuild, disk 16 had over 2000 errors and was x'd out.  

- I shut down the server and mistakenly pulled disk 12 and replaced it with a 6tb drive.

- Booted server, changed disk 12 to the new 6tb and was like why do I have two red x disks.  Also, the 6tb was given to me by a friend and I learned later that he secure erased it and the disk is locked.  <-- I think adding it in as disk 12 messed up the array.  I DID NOT TRY TO START THE ARRAY.

- Then, I finally realized I had pulled the wrong disk.  I shut down the server, pulled disk 16 (4tb with smart errors) and replaced it with a new 8tb drive.  I also put the original disk 12 (4tb) disk back in.

- Upon restart, I added the new 8tb in as disk 16.  All looked good, even disk 12.  I hit start and data rebuild started.  However, it was at this point that disk 12 said "Unmountable: No file system".  

- The array finished data rebuild and no disks are x'd out, but disk 12 still says "Unmountable: No file system".  Nothing is emulated and everything seems to be working.  

 

I don't know specifically what was on disk 12, but it was all stuff I don't really mind if I lose but I'd prefer not to.  (I move all critical data off a drive with smart errors and only leave movies and stuff).  I know, I know.  I shouldn't have any drives with smart errors, but at one point I had 6 and I couldn't replace them fast enough.  

 

So, how do I fix this and retain the data, or is it already to late.  If too late, that's fine, I'll just format the drive and move on.  

If another disk failed during the rebuild of disk12 the rebuilt disk will be corrupt, you can still try a filesystem check, though even if all looks well after that there will likely still be corrupt files.

Ok, so I ran XFS repair in maint mode.  All the data is in lost+found, so yeah, it's toast. I was able to get alot of file names from the xfs log so at least I know some of what was on the disk.  Thanks for the help.