Hello,

 

I was wondering whether it is possible (and how?) to recover data and the array after a fatal crash that left me with the parity drive as well as 2 other drives (out of 4). One of the drive is now missing and will remain so as some of the pins for the power are broken. The second drive is there and seems fine with SMART but is not available to the array and is disabled. As such the array is stopped with invalid configuration. 

 

Is there anyway to recover the data on the missing drive and get the array back up again? 

Thanks for any help.

The standard recovery methods will not work with 2 drives failed and single parity.

It might be possible to force Unraid to tread disk4 as valid and see if it can then successfully emulate disk1.  @JorgeB is the expert on this type of recovery so I would suggest waiting for him to chime in.

This will only work if parity is still valid:

 

-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all assignments and assign any missing disk(s) if needed, including the new disk1, replacement disk should be same size or larger than the old one
-IMPORTANT - Check both "parity is already valid" and "maintenance mode" and start the array (note that the GUI will still show that data on parity disk(s) will be overwritten, this is normal as it doesn't account for the checkbox, but it won't be as long as it's checked)
-Stop array
-Unassign disk1
-Start array (in normal mode now) and post new diags.

Thanks JorgeB. Sorry for the delay but I was waiting for a replacement drive to arrive. I followed the instruction and post the new diags below and the current status of the array after having unassigned drive 1 and restarting the array as advised.

What should I do now? any hope to rebuild drive 1 and recover the data? Thanks for your help. tower-diagnostics-20240110-0850.zip

Emulated disk1 doesn't mount.

 

Check filesystem on emulated disk1. Be sure to do it from the webUI, and capture output so you can post it.

Thanks. I don't know if I did what you asked properly. I initially couldn't get to the check filesystem even after clicking on the drive. It's simply wasn't there. The drive was ntfs so I reformated the disk1 to xfs and now it mounts and can be part of the array. I checked the file system status. I started the array in maintenance mode and the drive is part of it. The drive is emulated (and shows a SMART error although it's not clear why because it seems fine). Should I now click the SYNC button and try a data-rebuild? Would that possibly restore what was on the original disk1?

Thanks.

You need to run without -n (the no modify flag) to get a repair to run, and if it asks for add -L.

 

after doing that when you restart the array in normal mode the drive should mount.

So I ran it on disk1 with the -L flag and then started the array. it did rebuild overnight and now the array is up. I'm not sure that the data on disk1 are there however. I'm trying to mount the share and see if the data are there but it's taking a while. I will post tomorrow. 

 

On 1/11/2024 at 3:48 PM, gapinl said:

The drive was ntfs so I reformated the disk1 to xfs

If you formatted the disk all data there would be deleted, formatting is never part of a rebuild.

I reformatted the new drive that was ntfs to xfs. there were no data on the new drive (obviously). I followed what was posted. Was I misled?

 

35 minutes ago, gapinl said:

I followed what was posted.

Posted where? I don't see anyone asking you to format a disk in this thread.

The new disk1 that was added was ntfs. I made it xfs to be part of the array. That's it. The drive was brand new to obviously empty. I would assume as such that I didn't erase data. Am I wrong in this assumption? The array was then rebuilt with this new disk1 drive in place of the previous one. Are the data rebuilt or gone?

Unraid would format the disk during the rebuild, if you format it manually it will delete all data and update parity, since the emulated disk was unmountable the correct procedure would be to check filesystem:

 

On 1/10/2024 at 5:18 PM, trurl said:

Emulated disk1 doesn't mount.

 

Check filesystem on emulated disk1. Be sure to do it from the webUI, and capture output so you can post it.

 

I did the check filesystem with the -L flag on disk1. Then started the array and it did a rebuild overnight. As you can see in wednesday's post, when the drive was unmounted it was ntfs. When part of the array it was changed to xfs. I did change its format so it was part of the array. Was that my mistake?

After rebuild disk1 has only 27.9 Gb written on it. So I assume the data are gone? 

17 minutes ago, gapinl said:

Are the data rebuilt or gone?

If you formatted the disk after assigning it to the array, then parity agrees the disk has been formatted and rebuild can only result in a formatted disk.