Snapper

Install snapper

pacman -S snapper snap-pac

Generate root config

snapper -c root create-config /

Create pacman hook for /boot

File: /etc/pacman.d/hooks/50-bootbackup.hook

[Trigger]
Operation = Upgrade
Operation = Install
Operation = Remove
Type = Path
Target = usr/lib/modules/*/vmlinuz

[Action]
Depends = rsync
Description = Backing up /boot...
When = PreTransaction
Exec = /usr/bin/rsync -a --delete /boot /.bootbackup