Speed up the comparison

[stanleywong]

After the "initial" syncronise (A -->B) (each 500 GB harddisk), everytime when I add or delete the files from A, VV needs to "recompare" again before syncronise.

Is there any function could help to record and keep track of the "add" or "delete" of files of A, and it can syncronise from A to B QUICKLY without spending lots of time to "recompare" again and again, after my "daily" & "minor" update?

Is there any technology "photo shot" that can very quickly to "memorise" the whole structure and/or files of A, and then copy to B. When there's a failure of A, we can still get back all thing of A from B.