Windows Server® 2012 Unleashed

Planning for the Use of Snapshots on the Hyper-V System

A technology built in to Hyper-V is the concept of a snapshot. A snapshot uses the Microsoft Volume Shadow Copy Service (VSS) to make a duplicate copy of a file; however, in the case of virtualization, the file is the virtual server guest virtual disk.

The first time a snapshot is taken, the snapshot contains a compressed copy of the contents of RAM on the system along with a bitmap of the virtual disk image of the guest session. If the original guest image is 8GB in size, the snapshot will be significantly smaller in size; however, the server storage system still needs to have additional disk space to support both the original disk image, plus the amount of disk space needed for the contents ...