Deduplication
Storing only one copy of identical data blocks to save space, especially in backups.
Deduplicating backup tools like Restic and Borg store many daily snapshots while using a fraction of the space, because unchanged data is stored only once.
Related articles
Restic
A modern backup program that creates encrypted, deduplicated, versioned backups.
Backup
A separate, recoverable copy of your data kept to protect against loss, corruption or disaster.
Compression
Encoding data to take up less space, often transparently at the filesystem level.