Helllo UnRaid community,

One of my drives recently started giving me some SMART errors. It's a drive I had been meaning to upgrade for a while, and I have a new disk on the way to replace it.

A day or two after that started, a different disk suddenly started failing to mount. It shows "Device disabled, Contents emulated" and "Unmountable: wrong or no filesystem". However, I can't access any of the emulated contents.

I have 6 total drives, with only one acting as a parity drive.

I have tried to recover the filesystem both through the webgui and the command line. Each time I receive an error stating "xfs_repair: libxfs_device_zero write failed: Input/output error" during phase 7 and it fails. My understanding is that these were trying to repair the emulated filesystem, so I also tried running xfs_repair on the raw disk (/dev/sdf). It ran for a good 12 hours and then said something along the line of "failed to find secondary superblock".

I was also due for a PSU upgrade on this system, and considered power issues as a possibility, so I have replaced the PSU, and tried different SATA cables, and the errors persist.

I ran an extended SMART test on the disabled disk and it came back OK, attaching the results here.

What should my next course of action be? The new disk should arrive early next week. Should I wait until that arrives to attempt recovery with something like ddrescue?

None of this data is critical, but I'd still like to at least minimize data loss.

Any advice is appreciated. Thank you in advance!

WDC_WD60EZAZ-00SF3B0_WD-WX52DC1A4E93-20251214-0846.txt

Attach Diagnostics ZIP to your NEXT post in this thread.

50 minutes ago, Tevans93 said:

tried running xfs_repair on the raw disk (/dev/sdf)

That would be wrong. You have to repair the partition not the sd device.

Also you would invalidate parity even if you did the partition.

Using webUI will do it correctly.

39 minutes ago, trurl said:

Attach Diagnostics ZIP to your NEXT post in this thread.

Here's a couple diagnostics, one from today and one from last week when the problem started.

For reference, disk 3 is the one that won't mount, and disk 5 is the one that has SMART errors and was about to be replaced.

Appreciate the help!

plexserver-diagnostics-20251220-1817.zip plexserver-diagnostics-20251214-1051.zip

Possibly disk5 can't be read well enough to allow disk3 to be emulated accurately. Emulation requires all other disks to be accurately read.

Since both of those diagnostics were taken without the array started in Normal (not Maintenance) mode, no filesystems are mounted so can't tell anything about the contents of disk5 or emulated disk3.

Syslog from those older diagnostics do seem to indicate disk5 mounted though, and emulated disk3 didn't.

SMART for disk3 looks OK, possibly a connection issue disabled it and bad disk5 kept it from being emulated accurately.

There is a way to get disk3 back into the array and disable disk5 instead so it can be rebuilt.

1. Tools - New Config - Retain All - Apply

2. Check BOTH Parity Valid box and Maintenance Mode box, and start the array. This will accept all disks just as they are into the array and won't modify parity or any data disk.

3. Stop the array, unassign disk5, then start the array in Normal mode. This will disable disk5 and mount all disks including emulated disk5.

Then post new Diagnostics.

I followed the steps and here's the resulting diagnostics.

Thanks again for the help.

plexserver-diagnostics-20251220-1945.zip

Physical disk3 mounted and has plenty of data.

Emulated disk5 is not mountable.

Check filesystem on emulated disk5 from the webUI.

Ran check on the emulated disk 5. It found errors and I ran the repairs.

I started the array in normal mode after and the emulated disk 5 appears to be mounted now. Attaching diagnostics.

plexserver-diagnostics-20251220-2148.zip

Emulated disk5 has plenty of data now. You can browse the files if you want. You can even read/write the emulated disk. The emulated contents are exactly what will be rebuilt on the replacement disk. Since you only have single parity and one disabled data disk, you currently have no redundancy. Rebuild to a replacement ASAP.

Got it, thanks for the help! I have a replacement drive arriving this week and I'll rebuild once I get that installed.

One more question if you don't mind. Emulated disk 5 seemingly has a large amount of data in lost+found. The folder is ~460gb according to the webgui.

Do you have any recommendations on how to go about recovering that data?

10 minutes ago, Tevans93 said:

Do you have any recommendations on how to go about recovering that data?

Unfortunately it is a manual process. If you have decent backups normally much easier to restore files from them.

The Linux ‘file’ command can at least be used to tell you the content type of files with numeric names so that you can give them the right file extension to help with loading them into an appropriate program to look at their contents.