DPM 2012 R2 UR6, protecting many VM's. Some of them, have VHD's of 400 - 1500 GB. These VMs very often are backuped as full backup. 3 times a week backup downloads only changes, about 10GB of data. Other 4 times a week DPM downloads all VM's data on backup job, 400 - 1500GB of transferred data. Why ?
On these VM's nothing special is happening. they are just RDS or File server.