A. Hyper-V snapshots store the state, data, and hardware configuration of a running virtual machine (VM). They're intended to provide a quick rollback for VMs, particularly in test, evaluation, or demonstration environments.
Hyper-V snapshots are stored as .AVHD files. In Windows Server 2008 R2, these files are typically stored in the same folder as the VM's Virtual Hard Disk (VHD). Note that this is a different location than in Server 2008 SP2, where the .AVHD files are stored with the VM configuration files. You can change this location on a per-VM basis by adjusting the VM snapshot setting.
Be aware that you should never delete .AVHD files directly from their storage location. Instead, remove snapshots through the Hyper-V Manager interface. Also, never expand a VHD for a VM. This action will make the attached snapshots unusable. Also, it's generally a best practice not to keep snapshots around for a long time.