I just made a mistake (big one). I removed three old drives from the array and ran the New Configuration Utility. Unfortunately, I forgot about there now being the option of two parity drives, and I assigned one of my good data drives as a second parity, instead of as a data drive.

 

As the array was restarting, I realized my mistake but could not stop it. I unplugged the server, rebooted, and ran the utility again, this time with the drive as a data drive. However, I now have an error message that says "Unmountable: No File System".

 

Is there any way to restore the prior file system?

 

Thanks, Carl.

Might still be able to recover with the invalid slot command if the disks are using xfs (or reiserfs), but note that parity won't be 100% in sync due to mounting the other disks, still worth trying, need to know what Unraid release you have and the disk # you want to rebuild.

Thank you for your response. I'm using version 6.8.3, but the disk at issue no longer has a number, as I started the array w/o that disk to avoid anything being written over it (Hopefully that didn't destroy any chances of recovering information, but I didn't write down the disk order before I did the new config, so couldn't figure out a way to start the array in the same disk order).

 

Carl.

Order doesn't matter with single parity. However

6 hours ago, JorgeB said:

note that parity won't be 100% in sync due to mounting the other disks

If I understand your first post correctly, I suspect parity may be far from valid at this point, since you were shrinking the array.

 

Parity might be less out-of-sync if you put those other disks back in.

 

Wait for @JorgeB to comment further.

When I launched Unraid, it started I set it to rebuild parity on that one parity drive (which I'm also sensing was a mistake?) I guess I was kind of hoping there's a solution for the drive concerned, such as an unformat command, to simply unroll whatever Unraid managed to do in the 1 minute it was labeled as a parity drive.

 

The good news is none of your other data disks should be affected, and since each disk is an independent filesystem, all the files that were on those disks should be fine.

 

Do you have backups? You must always have another copy of anything important and irreplaceable. Parity only helps you recover from a failed disk. Lots of other more common ways to lose data, including user error.

2 hours ago, Carl314 said:

to simply unroll whatever Unraid managed to do in the 1 minute it was labeled as a parity drive.

Unfortunately, the drive's content list is most likely permanently gone, so recovery is probably going to be at best a jumbled mess of unsorted blocks of data that the recovery program may be able to deduce may be part of a file.

 

It's the logical equivalent of taking a well organized wall of filing cabinets with thousands of labeled folders with various chapters of books and documents and upending the pages in those folders and drawers all over the floor, removing all the folders and labels, and giving the pile of loose paper a good kick just to be thorough. Your data is almost all still there, but putting humpty dumpty together again is a monumental task.

 

What types of files were stored on that drive?

Nothing irreplaceable - primarily blu-rays I can rip again. But pretty time-consuming.

Wouldn't hurt to try one of the recovery programs on it to see if it finds any content, but I suspect it would be quicker and easier to re-rip from source.

22 hours ago, JorgeB said:

with the invalid slot command

This really won't work, since I forgot an important detail for this case, when the beginning of the data disk was wiped parity was also synced without that disk, so there's no way to recover using the invalid slot command, best bet is to use a delete file recovery utility like UFS explorer.