Mac OS X 10.5 Leopard: the Ars Technica review: Page 7

To prevent events from being logged at all for changes to a particular volume, simply create a file named no_log in the .fseventsd directory on that volume. And in case it doesn’t go without saying, FSEvents honors the Mac OS X access control rules; you cannot receive events about directories that you don’t have permission to read.

I wonder if I could place a no_log on my clone volume and keep it when the rsync happens?

The description of FSEvents is short and to the point. Something a deep-down OS geek can appreciate 😉

I knew that *something* had to be keeping track of changes – 20 seconds for an hourly Time Machine backup is nice and unobtrusive.