Raid group unmounted after adding new disk and choosing to expand

[Feylong72]

I'm really stumped on this one and tried my best to figure out what exactly is wrong here but not sure, so would greatly appreciate any help.

I had a 14TB + 8TB in a simple raid 1 with no snapshots and no storage pools using a static volume formatted with 8k blocks.
I added another 8TB (Same make as the previous) and went through the expand raid wizard.
Everything seemed to be working and I left it for a few hours.
When I logged back in using HTTP I started getting errors popping up and wizards asking me to create a new storage pool/volume!
I cancel all those and when I finally got to the storage options it shows the raid group as there but just says unmounted. I have tried the 'check' but after a minute or so nothing appears to have happened.
If I reboot and log in then there is a warning in the log just saying unable to mount.

If I SSH into the device and run md_checker I get this:-

RAID metadata found!
UUID: b1650eae:eaa82dcb:f06fa867:047d469b
Level: raid1
Devices: 1
Name: md1
Chunk Size: -
md Version: 1.0
Creation Time: May 5 18:29:51 2021
Status: ONLINE (md1)
===============================================================================================
Enclosure | Port | Block Dev Name | # | Status | Last Update Time | Events | Array State
===============================================================================================
NAS_HOST 1 /dev/sdb3 0 Active May 7 19:35:59 2021 2 A
===============================================================================================

RAID metadata found!
UUID: 5fafc1ee:6ec1f4c3:bfd1d76d:6ed530d7
Level: raid1
Devices: 1
Name: md2
Chunk Size: -
md Version: 1.0
Creation Time: May 6 12:07:16 2021
Status: ONLINE (md2)
===============================================================================================
Enclosure | Port | Block Dev Name | # | Status | Last Update Time | Events | Array State
===============================================================================================
NAS_HOST 2 /dev/sdc3 0 Active May 7 19:35:59 2021 2 A
===============================================================================================

RAID metadata found!
UUID: 3b4370dd:056a460d:c5e207a7:0cf14405
Level: raid1
Devices: 1
Name: md3
Chunk Size: -
md Version: 1.0
Creation Time: May 7 16:21:41 2021
Status: ONLINE (md3)
===============================================================================================
Enclosure | Port | Block Dev Name | # | Status | Last Update Time | Events | Array State
===============================================================================================
NAS_HOST 3 /dev/sda3 0 Active May 7 19:35:59 2021 3 A
===============================================================================================

Any suggestions on what to try to get it mounted?

[dolbyman]

RAID0 is a dead end .. no drives can be added to it , so it's unclear what you did

did you just edit the raid0 to raid1 ?

so a raid1 needs to be changed to raid5 to add another drive .. is that what you tried to do ?

[Feylong72]

RAID0 is a dead end .. no drives can be added to it , so it's unclear what you did

did you just edit the raid0 to raid1 ?

so a raid1 needs to be changed to raid5 to add another drive .. is that what you tried to do ?

yes sorry I double checked

[dolbyman]

still not sure what happened .. it looks like pooled single disks, but you said you have a static volume

what was the resulting volume size of your 8TB+14TB volume ?

On raid one it should have been around 7TB effective

[Feylong72]

It was around 19TB. I originally started with just the 14TB and when that got almost full I added the 1st 8TB and after I almost filled that up I decided to add a 3rd drive. I just chose the options when initializing the disks that I wanted a simple volume I could keep expanding. This isn't the 1st time I have done this with this qnap NAS.

[dolbyman]

So if it was anything other than 7TB it was NOT RAID1

Spanning JBOD or RAID0 would have not offered any expansion .. so my bet is still on pooled single drives.