Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Thursday, August 11, 2011

Managing Snapshots in Hyper-V

Taking snapshots

Taking a snapshot is a very easy process. Just remember a few considerations first.

1. Make sure the disk that is holding the virtual machine (VM) folder has the disk space for a snapshot.

2. Make sure the VM is either running, or shutdown. You cannot take a snapshot while the VM is paused.

3. Snapshots are not supported in a production environment. Snapshots are good for lab or test environments.

4. Snapshots are not a replacement for regular backups.

You can take a snapshot in one of two ways; you can right click a VM in Hyper-V Manager and select Snapshot. Your other option is to click on the VM in Hyper-V Manager and click Snapshot from the VM specific menu in the lower left hand corner of the Hyper-V Manager.

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It will take several seconds for the snapshot to appear in the Snapshots window.

 
 
Reverting snapshots

Snapshots make it very easy to go back to a point-in-time. You can easily reset a VM back to its current snapshot by doing a Revert. To Revert a VM, right click the VM in Hyper-V Manager. Click Revert.

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This will make the VM fall back to the last Snapshot taken or the last snapshot applied, whichever is the case.

 
 
merging snapshots

Merging a snapshot is the result of deleting a snapshot from Hyper-V. To merge a snapshot into its parent, right click the snapshot to delete and select Delete Snapshot Subtree. Click Delete when prompted.

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A word of caution on this procedure. Take a look at the example below:

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If I were to merge the snapshot label VTEC1 with its parent Network Base 1, the results would be catastrophic for the snapshots 6416C – AD Recycle Bin and 6420 No DHCP. That is because differencing disks are used for snapshots. All three snapshots in questions are children of Network Base 1. By merging VTEC1 into Network Base 1, I make the other two snapshots unusable.

Perform this procedure with caution.

 
 
Deleting snapshots

From time to time it is good practice to remove snapshots that you no longer need. This will help to conserve on disk space and help to make the VM more portable.

In Hyper-V Manager, right click the snapshot you want to delete and click Delete Snapshot.

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Then click Delete when prompted.

The Snapshot will be removed from the list and the disk.
 
 
Applying snapshots;

Applying a snapshot is very easy to do. You can apply a snapshot with the VM running or turned off. In Hyper-V Manager, you apply a snapshot in one of two ways. Right click the snapshot and Click Apply or click the Snapshot and click Apply from the VM menu on the lower left.

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Hyper-V will asked you if you want to just apply the Snapshot or if you want to take one of the current machine state before applying the snapshot you selected.

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The VM will now be configured to that snapshot.

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