I’m backing up a lot of data every day to GDrive, although the daily difference is really limited. At this moment, rclone checks every folder on both destination as source.
Would it be an option to also implement the Cache-feature to commands like copy & move?
You should be able to wrap the drive in a cache and it work just fine for copy and move. I don’t think many people are using cache like this at the moment, so test it first!
It should work just fine on non-mount commands too. In fact most of the automated tests are done in a similar way.
Just make sure to not run with --cache-db-purge as it will basically start from an empty cache every time.