Hi all,

 

I’m running an Unraid 6.12.6 with x2 parity and x8 data disks. Four of the data disks (Disk1 to Disk 4) were running reiserfs and I made the decision to move the data of each disk in turn and reformat to zfs.

 

I moved all the data from disk1 using the unbalance plugin. Stopped the array and changed the format of the drive to zfs, started the array and then clicked the prompt to reformat. This worked fine and I repeated with Disk2 which also worked fine.

 

I repeated the above with disk3 and after stopping the array, changing the disk 3 format to zfs and then starting I was presented with two messages indicting ‘Unmountable disk present’ for both Disk 2 and disk 3.

 

For Disk 3 this would be expected as this is empty and now needs needs formatting to zfs, but not Disk 2 as this contains data.

 

How do I recover my data for disk2?

 

Thanks in advance

hmnetworkstore-diagnostics-20240106-0827.zip

Edited January 7, 20242 yr by Kez
typo

This can be caused by a bug with unaligned disks, reboot and post new diags, are don't format any disks for now.

Hi, thanks for investigating.

 

The first logs I attached were after reboot. Here is another set of logs.

 

 

hmnetworkstore-diagnostics-20240107-1243.zip

Edited January 7, 20242 yr by Kez

Since disk3 has the same capacity and is also unaligned you can use it to restore the MBR, sdf and sdg are disks 3 and 2 respectively according to last diags, if you rebooted since make sure they didn't change, then type:

 

dd if=/dev/sdg of=/boot/disk2.mbr bs=512 count=1
dd if=/dev/sdf of=/dev/sdg bs=512 count=1

 

The first command will backup current disk2 MBR to the flash drive, second one will copy the MBR from disk3 dos disk2, after doing that reboot and disk2 should now mount, if it does you can format disk3, after formatting stop array, start array, disk3 will no longer mount, copy the MBR from disk2 to disk3 and reboot, and disk should now also be fixed.

Hi,

 

Followed your direction and that all worked exactly as you indicated. All disks are now mounted. Thank you.

 

Is there anything I should do after like run a parity check? I did a Party check 5 days ago for before changing the drives over to zfs.

 

If this is a known bug will this be fixed in the future?

Edited January 7, 20242 yr by Kez

Nothing else you need to do, and yes, it's a recently discovered bug, it will be fixed for v6.12.7