Syncing two drives where either one is always offline

[David.P]

Suppose I have two PCs "A" and "B" at different locations, and only one of them is running at any point in time.

Each PC has a 1 TB data drive which should be kept in sync either via a USB stick or, preferably, via a cloud storage. Both the USB stick and the cloud storage however are much smaller, say, at 50GB.

Is there a sync workflow that uploads only new and changed files from PC "A" to the USB or cloud drive, and then, when PC "A" is turned off and PC "B" is turned on, syncs the changes from the USB or cloud drive to PC "B" -- and vice versa?

The same scenario is described here; and there seems to be a specialized tool for this very task.

Is this possible with FreeFileSync?

[xCSxXenon]

That is not currently possible. You would have to exclude all the "extra" data that already exists on 'B' when syncing up to the cloud/USB from 'A'. It would possible, just convoluted.