merge

Hi, Apologies if this has been posted else where but I have checked. Background:- Ds920+ Volume 1 - 2 x 10TB EXT4 Volume 2 - 2 x 10TB BTRFS I have migrated ALL shares from V1 to V2. How would I migrate all services (apps, logs, OS, BOOT etc) to V2 so I can delete V1 and eventually merge...