You should create a snapshot, or checkpoint (as they are called in System Center Virtual Machine Manager), right before you make any known change to your VM that would require some sort of system or application restore if the configuration, patch or application upgrade went wrong.
Snapshots are a recovery point that saves the state, data and hardware configuration of a VM. Now, With Hyper-V in Windows Server 2012, the creation and deletion of a snapshot happens without VM downtime. The process can be scripted, but it is most commonly done manually, either by an application owner or by a virtualization system administrator, before any changes are made to the VM. These types of snapshots are different from conventional host-level backups of VMs, but use the same underlying VSS Hyper-V Writer, which is installed when you enable the Hyper-V role, to prepare (quiesce) the memory and I/O state of the VM, in order to precisely capture its state at that moment. However, the outcome of these two processes differs.
When you create a snapshot… Read the rest of the article HERE
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