+Say for instance you create a VM with a 32GB hard disk, and after
+installing the guest system OS, the root file system of the VM contains
+3 GB of data. In that case only 3GB are written to the storage, even
+if the guest VM sees a 32GB hard drive. In this way thin provisioning
+allows you to create disk images which are larger than the currently
+available storage blocks. You can create large disk images for your
+VMs, and when the need arises, add more disks to your storage without
+resizing the VMs' file systems.