Arvin Schnell, 01 March 2017
Snapper was just improved to work with a read-only btrfs root filesystem. You may ask who needs that. Well, SUSE needs it for the new CaaSP product, which has a read-only root filesystem and uses transactional updates.
Transactional updates work by creating a snapshot of the system and then updating the packages in that new snapshot. This way the update does not affect any of the running services. Instead the update is activated by a reboot. A read-only root filesystem on a system with transactional updates simply ensures that the update does not accidentally modify the running system.
For more information read the announcement of transactional updated.
This feature is available in snapper since version 0.4.3.