fast backup of my notebook - contains gigabytes of audio/video/photo and VM images

Problem:

• full backup (close to 1 TB) takes over 5 hours
• no history (due to limited storage) 

Solution:

• btrfs + snapper
• hourly snapshots
• snapshots before/after install/update of packages (via emerge hooks)

Challenge

• automated incremental backup of snapper snapshots
• automated retirement of backup snapshots following the main system snapper retirement
• automated restore to a fresh volume in case of disaster