Mit dieser Hilfe und ein paar Abänderungen erfolgreich in eine Synology eingebunden.

I had the the same problem with an SHR-Raid on a Synology Diskstation. Tried over 1 Week to solve the same problem. The first i can say you have to work with the terminal. The 2nd is that you need the mdadm package.

#   sudo apt-get install mdadm

then you have to check how the drive is registered in Ubuntu „“dev/sdc or something like that. The next input says linux that you want to run this drive as a volume

#   mdadm -A --verbose --run /dev/md3 /dev/sdc5

with that input you force linux to use this as volumegroup

#   mdadm -Sf /dev/md3

#   pvscan

gives back following information

#   File descriptor 4 (/dev/urandom) leaked on pvscan invocation. Parent PID 2451: bash
#     PV /dev/md3   VG vg1   lvm2 [1,81 TiB / 0    free]
#     Total: 1 [1,81 TiB] / in use: 1 [1,81 TiB] / in no VG: 0 [0   ]

with the next you make the volumegroup to a disk

#   vgchange -ay /dev/vg1
#   lvdisplay vg1

If you made this steps correctly you can find your drive in personal Folders under ubuntu an you can mount the drive then. If you want you can mount with terminal too:

#  mkdir /media/syno-vg1
#  mount /dev/vg1/lv -o ro /media/syno-vg1

Hope it works.