Restic
A modern backup program that creates encrypted, deduplicated, versioned backups.
Restic can back up to local disks, another server, or cloud storage, and its snapshots let you restore any previous version. It's a favourite for the offsite copy in a 3-2-1 strategy.
Related articles
Backup
A separate, recoverable copy of your data kept to protect against loss, corruption or disaster.
Deduplication
Storing only one copy of identical data blocks to save space, especially in backups.
rsync
A fast tool that copies and synchronizes files, transferring only what changed.