Hyper-V: How to Work with CheckPoints

CheckPoints provide a fast and easy way to revert a Virtual Machine in Previous State.Can be very usefull for IT , System Administrators to recreate a specific problem or condition to troubleshoot a problem and when finish to revert back in previous state. CheckPoints can be use for certain circumanstences which make sense. For example you can use checkpoint in production enviroment before proceed with an update of a software running. But it's not prefer to use Checkpoints in Virtual Machines which provide sensitive services or availability of storage is low.

Hyper-V CheckPoints are very useful and i will proceed with the following subjects:

Create a check point

Open HYPER-V Manager

Right Click in the Virtual Machine that you want and select CheckPoint.

http://www.askme4tech.com/sites/default/files/hyper-v-checkpoint-select.png

You can see the CheckPoint that created with some details like date and time.

http://www.askme4tech.com/sites/default/files/hyperv-checkpointnow.PNG

For more technical details when create a CheckPoint in the Path of the Virtual Hard Disks or in the Default Path C:\Users\Public\Documents\HYPER-V\Virtual Hard Diksk creted an AVHDX File.

http://www.askme4tech.com/sites/default/files/hyperv-checkpoint-avhdx.PNG

When to delete checkPoint and the AVHDX File

Let's create a very very simple Scenario just to clear understand the power of CheckPoint.

We need to move a folder in the Desktop of Windows Server 2008.

We start to Move the folder in the Desktop of Virtual Machine. The folder moved successfull without problems.

http://www.askme4tech.com/sites/default/files/windowsserver-createnewfolder.PNG

Right Click in Check Point that has created and select Delete CheckPoint. Click Delete.

http://www.askme4tech.com/sites/default/files/hyperv-delete-checkpoint.PNG

Watch the Status of the Virtual Machine.

http://www.askme4tech.com/sites/default/files/hyperv-checkpoint-deletestatus.PNG

All tasks proceed without problems.

Apply a snapshot

Now i will explain what happened if after create the CheckPoint the task that apply it's not going very well and have issues with Virtual Machine.

Here we represent only with a very simple example as to move a folder in the Desktop of Virtual Machine

We start to Move the folder in the Desktop of Virtual Machine. Oops something going wrong with the transfer. We must go back before move the folder in the Desktop. Right click in the CheckPoint that have created and select Apply. You can select and Create CheckPoint and Apply. This option create another one checkpoint when apply the CheckPoint.

http://www.askme4tech.com/sites/default/files/hyperv-apply-checkpoint.PNG

In this example we Select Apply and watch the Status of Virtual Machine.

http://www.askme4tech.com/sites/default/files/hyperv-apply-checkpoint-restoring.png

When Apply the CheckPoint the Virtual Machine loose the connectivity because restoring in Previous State. Login in Virtual Machine and you can see that the folder which have created it's not exist anymore.

http://www.askme4tech.com/sites/default/files/windows-servers-afterapply-checkpoint.PNG

Imagine that you have a Production Server and want to apply a Software Update but it's not install successfull and the users can't Work. If you have create a CheckPoint before start the installation when you see that you have problem with the update ypu can restore it in State before start the Installation.

Very very useful for Test Servers , Labs.But for Production Enviroments only in some circumanstences.

As said in the beginning Microsoft not recommend to use CheckPoints in Virtual Machines which provide senitive services.

For Example you can't use Check Point in Domain Controller if you have and 2nd Domain Controller which Replicated.

Because after apply CheckPoint in the Domain Controller the Replicated Domain Controller will find the changes as oudated and here start THE BIG PROBLEM.

One Last thing.

 Don't use CheckPoints as BACKUPS. It's different a Backup from CheckPoint.