How to keep two remote drives in sync without connectivity?

[chcat]

Is it possible with FFS to compare a drive against a batabase file, then put the files that differ to a USB stick, then move to another place/town, copy the files to the other drive, update the database file, return to the first place, do some work, compare the drive against the updated database file, and so on.

[Plerry]

By running similar FFS Two-way variant syncs at both/multiple locations versus a portable disk, e.g. a USB stick, you should be able to achieve what you describe, with the exception that the portable disk would contain all data in the sync and not just the delta/differences.