Thanks for the reply. I do understand the 4096 byte directory size.
What I really meant was the size I get in du -sh. Please see the size below.
diff backup is bigger than full backup and we don’t get that much data in a single day.
du -sh 2016-03-05T193001Z-full
5.5G 2016-03-05T193001Z-full
du -sh 2016-03-06T193002Z-diff
5.6G 2016-03-06T193002Z-diff