Tempus Machina aims to provide a macOS (nee OS X) Time Machine work-alike powered by rsync, especially the tmutil command line utility.

IBS provides a very useful, very capable disk-to-disk backup system. After the first backup run, all following backups are incremental based on the previous backup, and yet through the magic of Unix hard links, each individual backup LOOKS like a "full" backup, but only takes up disk space incrementally.