OK, I expected that there would be a simple command to integrate a new repository. It should be included into Nakivo documentation.
Fortunately I have good Linux knowledge, so I did it.
What do I have to do to remove the old Onboard Repository which is unneeded now?
I would remove it from /etc/fstab, remove logical volume, delete partition /dev/sdb and finally remove the 500GB disk from the VM.
Is it enough? Or are additional steps needed to remove it properly?