Harddisk Size with DD

So we DD in a 20GB image onto a VM with a 10GB iscsi disk. It works but now the bootdisk size shows up as 0gb. Inside the VM it shows the right size (the size of the image).

Will this cause any issues on our SAN? Also conversely, if we do a backup of this system and restore it - will it work? Given the disk image is 20GB but the config file shows 10GB?