I will test today with the new test image.
Curently I have the same issue with a 4*3 TB disk group, expanded to 5*3 TB disk group. The Disk group is extended with 5 disks, but when I expand the volume, it stucks, and after a few hours I can't connect to the synology webpage.
Another issue that I have discovered now, is when I copy data from the Synology disks, with more than 70MB/s after 30-40 min the server is not respinding. I can connect on CLI, but the GUI is down, and the mounted drive is not accesible.
5*3 TB Disks
Hyper-V - Physical HardDrive
I have tried to boot from the img( converted to iso, but it didn't boot.)
Can you help me with another version?