[willvarfar]

Classic source control had this problem.

The clever trick is to reencode the previous most-recent backup as a delta from the current state, and do a full-backup of the current state, rather than encoding each new backup as a delta from the previous state (which becomes slower and slower to compute, the more previous states you have).

Problem solved :)

[tatersolid]

That's really expensive when your previous backup is on cloud storage

[willvarfar]

To compute a delta, you need the previous version. If this previous version is computed from a single file - the previous snapshot - then that's actually less data and effort than if its computed by taking an old snapshot and replaying all the deltas upto the current time.