ReadyNAS NVX problems replacing disk

Hi,

Yesterday I received a notification that one of the disks in my ReadyNAS NVX was dead and required replacement.
I had a spare disk of the same kind (it is the 3TB Hitachi that is listed in the HCL), so I performed a replacement (with the unit on).
I got two more notifications. First "Disk removal detected. [Disk 3]" and then "Data volume will be rebuilt with disk 3".

After this, nothing happens. The volume is not being rebuilt and both Frontview and RAIDar report disk 3 as dead. I left if for some time after reading that it sometimes needs a few minutes to start the rebuild, but nothing happened.

I had also read that sometimes rebooting the unit is necessary, which I did, but still the unit is marked as dead and rebuild does not start (I still get the "Data volume will be rebuilt with disk 3" message).

The disk that was reported dead actually seems to be just fine. I tried it on my PC, created new file systems and everything works fine. A long smart test did not reveal any issues either.

I then tried to re-insert the original disk (after removing all partitions) and same thing happens. I get the notifications that the disk was removed and that a the data volume will be rebuilt.
Left it overnight, but nothing happened. It did not rebuild.
The data on the unit is still accessible, so that is not the problem, but I have no redundancy.

I tried many other things:

- Removed disk 3, restarted the unit. Frontview reports disk 3 as dead (with the capacity and model number), when it should be “missing” or “not installed”
- Inserted replacement disk. Shut down unit, powered it on again.
- This is the output of fdisk (through an ssh session on the unit)
~# fdisk -l /dev/sdc


fdisk: device has more than 2^32 sectors, can't use all of them
Found valid GPT with protective MBR; using GPT

Disk /dev/sdc: 4294967295 sectors, 2047G
Logical sector size: 512
Disk identifier (GUID): 8b974a2e-8823-42a2-ba93-113c35cb58fd
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134

Number  Start (sector)    End (sector)  Size       Code  Name


It basically reports no partitions
- dmesg reports


sdc: unknown partition table
 sdc: unknown partition table
 sdc: unknown partition table
 sdc:


- I even tried putting in another disk, that I know works fine, but with a smaller capacity (1TB). It was detected by the system, I got a notification that the disk was too small for the current volume, but Frontview still reported the disk as dead, but with the old capacity and model number.

I have had the unit for about 2 years and have performed expansion from 1TB to 2TB and later 3TB for each of the 4 drives. Never had any issues and I also replaced 2 failed disks during this time and that also worked fine.

Any clues on what might be the problem?

Is there a way to force the unit to mark the disk as not present/missing?
Thanks.