I'm running Time Machine on a new NAS. Until today, I used to run it on an USB drive. I am reusing the old job using the new 10.8 feature that allows me to add new backup targets.
When I configure the backup job in the system settings - there are some things like VMs that I want to exclude - Time Machine estimates the backup size to be 109 GB.
When I start the backup, however, it talks about 235 GB. I don't like this, as I don't want to litter the NAS with unnecessary data.
Is it normal that Time Machine shows such a huge difference between the System dialog, and the actual backup?