Hi folks. Pretty new to Unraid. Three-disk array, two cache drives. I do not currently have a parity disk. I know this is stupid, so if I'm SOL, fair enough.

Running into the "unmountable: wrong or no file system" problem with a drive I added recently. I precleared it before adding it to the array, and it was showing up fine for a few days. I updated to 7.2.5 in this time, if that matters. On Saturday, I powered back up after adding an HBA card; Disks 1 and 3 (14TB and 4TB) have been fine, but Disk 2 (8TB) has shown the error ever since. I've tried different combinations of power and data cables, and the issue seems to stay with Disk 2.

I ran xfs_repair via the GUI (I am comfortable with command lines in general, but haven't used Unraid's yet). Couldn't find the primary superblock, not enough secondary superblocks with matching geometry. I then let it search for a secondary superblock for over 24 hours before giving up.

SMART report on the drive had no errors, and I'm not seeing any Attributes that look overtly concerning. If it matters, before I formatted it for Unraid, this drive was partitioned into 2x 4TB as an external storage and backup location for a Mac Mini.

I've read a few posts on this topic, but wanted to check in with someone before I make it worse. How best should I proceed to potentially fix this and recover the array data on that drive?

Thank you in advance for any help.

formenas-diagnostics-20260511-0803.zip

37 minutes ago, edvardcrunch said:

If it matters, before I formatted it for Unraid, this drive was partitioned into 2x 4TB as an external storage

What do you get from command line with this?

fdisk -l /dev/sdc

What was the command used for xfs_repair?

It does appear to have a valid xfs filesystem

May 11 08:02:13 formenas kernel: XFS (md2p1): Mounting V5 Filesystem 132add9d-0613-480a-9cf7-d782f7feb285

May 11 08:02:13 formenas kernel: XFS (md2p1): totally zeroed log

May 11 08:02:13 formenas kernel: XFS (md2p1): Corruption warning: Metadata has LSN (1:9) ahead of current LSN (1:0). Please unmount and run xfs_repair (>= v4.3) to resolve.

Thank you both.

41 minutes ago, trurl said:

What do you get from command line with this?

fdisk -l /dev/sdc

fdisk: invalid option -- '1'

Which I'm guessing means no partitions. I did format the drive before bringing it into Unraid.

15 minutes ago, JorgeB said:

What was the command used for xfs_repair?

It does appear to have a valid xfs filesystem

May 11 08:02:13 formenas kernel: XFS (md2p1): Mounting V5 Filesystem 132add9d-0613-480a-9cf7-d782f7feb285

May 11 08:02:13 formenas kernel: XFS (md2p1): totally zeroed log

May 11 08:02:13 formenas kernel: XFS (md2p1): Corruption warning: Metadata has LSN (1:9) ahead of current LSN (1:0). Please unmount and run xfs_repair (>= v4.3) to resolve.

Just the Check Filesystem Status GUI option with the array in Maintenance mode. As I say, it ran for over a day without finding any secondary superblocks. Happy to try again via the command line if that would help.

2 minutes ago, edvardcrunch said:

fdisk: invalid option -- '1'

This looks like you put the numeral 1

fdisk -1

instead of the letter l

fdisk -l

Better to copy/paste instead of trying to type it yourself

Welp, I'm a dullard. Apologies.

Disk /dev/sdc: 7.28 TiB, 8001563222016 bytes, 15628053168 sectors

Disk model: WDC WD80EZAZ-11T

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disklabel type: dos

Disk identifier: 0x00000000

Device Boot Start End Sectors Size Id Type

/dev/sdc1 1 4294967295 4294967295 2T 0 Empty

Partition 1 does not start on physical sector boundary.

That is a precleared partition layout, not a regular one.

Type

dd if=/dev/sdc bs=16M status=progress 2>/dev/null | hexdump -C | grep 'XFSB'

Let it run for a couple of minutes, and post the output, assuming there is one.

I let it sit for around 5 minutes, got scared I did it wrong, then tried again. No output either time, it just sits after I hit Enter without posting any additional messages.

Make sure you are doing this with the array stopped, and if there's still no output, it suggests the disk was added to the array, but never formatted.

Ah, thanks for clarifying; the array was still in Maintenance mode. Ran it again with the array stopped for a few minutes, still no output.

Forgive the potentially obvious question, but if I added the disk to the array without formatting it, I assume it won't have been used to store any data, and I can safely format it without losing anything?

If it was never formatted, you will not have written any files or folders to it in the normal sense.

Many thanks to you both for the help.