About Virtual Machine Checkpoints
By creating checkpoints for a virtual machine, you can restore the virtual machine to a previous state. A typical use of checkpoints is to create a temporary backup before you apply update the operating system. The checkpoint enables you to revert the virtual machine to its previous state if the update fails or adversely affects the virtual machine.
What Is a Checkpoint?
Each checkpoint saves the state of each virtual hard disk that is attached to a virtual machine and all of the hard disk's contents, including application data files.
Use the Recover action to restore a virtual machine to its state when a checkpoint was created. For more information, see How to Restore a Virtual Machine to a Checkpoint. When you no longer need to recover a virtual machine to a checkpoint, you should merge the checkpoint to delete the associated files and recover disk space. For more information, see How to Merge a Checkpoint.
You can create as many as 64 checkpoints for any one virtual machine. However, checkpoints use disk space and, when allowed to proliferate over long periods, can affect performance during operations such as migrating a virtual machine. For this reason, it is a good practice to routinely merge unneeded checkpoints.
Checkpoints are portable. When you migrate, store, or deploy a virtual machine, any existing checkpoints move with the virtual machine.
You can create checkpoints only when a virtual machine is deployed on a host. You cannot create checkpoints when a virtual machine is stored in the library.
It is advisable to shut down the virtual machine before creating a checkpoint. However, you can create a checkpoint while a virtual machine is in a Stopped or Turned Off state. Doing so stops the virtual machine momentarily while the checkpoint is created. If Virtual Machine Additions is not installed on the virtual machine, the virtual machine is not shut down. Instead, it is simply stopped; this is similar to switching off the power on a physical machine while it is still running. To avoid losing any data, ensure that the virtual machine is not in use and that no processes are running on the virtual machine.
Several entry points are provided for creating checkpoints. You can use the New checkpoint action for a selected virtual machine, or you can create and manage checkpoints while updating the properties of a virtual machine. For more information, see How to Create a Checkpoint.
You can grant self-service users permission to create and manage checkpoints for their virtual machines. For more information, see How to Grant Virtual Machine Management Permissions to Self-Service Users. For information about creating checkpoints through the VMM Self-Service Portal, see Self-Service Portal Help on the portal Web site.
Checkpoints Are Not Intended for Backup
Checkpoints provide a temporary backup when you need to restore a virtual machine to a previous state after a change such as a system or application update. However, you should not use checkpoints for the permanent backup of the operating system, applications, or files.
Checkpoints are stored with the virtual machine on the host. Therefore, if the host fails while the virtual machine is deployed, the checkpoints are lost. To provide data protection for your virtual machines, you should instead use the Volume Shadow Copy Service (VSS) writer for Virtual Server or a backup application such as System Center Data Protection Manager (DPM) to back up your virtual machines to external storage. For more information, see the "Backing Up Virtual Machine Manager" topic at http://go.microsoft.com/fwlink/?LinkId=103031.
If your virtual machines store user data files, it is important to back up the data files on a virtual machine before you restore the virtual machine to a checkpoint. When you restore the virtual machine, user data files on its virtual hard disks are returned to their previous state.