I can't answer your question directly, but I can say that it is not strictly the number of bytes that are different that matters, but also how the differences are distributed in the file. Unless you explicitly set the block size, rsync uses a size that is the sqrt of the size of the file, thus bounding the worst case for the total volume of data transmitted (block summaries *plus* block data for changed blocks). If many of these sqrt-n-sized blocks are affected, then many will be transmitted. If you know more about what tends to happens with your files, you can adjust the block size.
(This is all from memory from reading the rsync tech report some time ago, but I think it remains sounds. I'm sure someone will correct me if I am off base.) Best wishes -- Eliot Moss -- Please use reply-all for most replies to avoid omitting the mailing list. To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
