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  • Managing Virtual Environments - How Hyper-V Snapshots Work

    Hyper-V snapshots create recovery points for a virtual machine (VM) so that it can be returned to a previous state later if needed. Snapshots can be taken regardless of whether the VM is running and are completely transparent to its operation. They can save countless hours, allowing an administrator to revert the system's state to a previous point in time when all was well, avoiding sometimes-painful tape restores.

    But you need to understand a few intricacies of the technology to make your experience with snapshots more reliable and less problematic. In addition, you must coordinate the timing of the snapshot, which brings the whole process together.<...

  • Changes to virtual machine snapshots in Windows Server 2008 R2

    Ben Armstrong: In Windows Server 2008 R2 we have made some surgical changes to the way virtual machine snapshots work and how they are exposed in the system in order to address some key customer pain points.  Changes include:

        * You can now export a single snapshot from a virtual machine.  This works by selecting the snapshot in question and then selecting Export… from the Action pane.  We will merge all the snapshot disk data into a single new virtual hard disk – and the resulting exported virtual machine will look like a virtual machine with no snapshots that is identical to the snapshot you selected.  Note that the virtual machine needs to be turned off in order to perform this operation.
        * Snapshot AVHD files are now created in the same directory as their parent VHD files.  Their names have also been updated to include the name of the parent virtual hard disk.  Both of these changes make it easier to identify and group snapshot files.
        * When you open the settings for a virtual machine snapshot and look at the hard disk settings – you will see the name of the AVHD that is associated with that snapshot.  This helps you to map AVHD files to specific snapshots.
        * You can now edit AVHD files in the edit VHD wizard.  This means that if you want to manually merge AVHD files to a new VHD to give to someone else – you can (note: be careful as you can cause problems if you merge back into the parent in this case).
        * You can now directly attach an AVHD file to a virtual machine.  This is very handy if you have lost your virtual machine configuration and need to get data off of a snapshot file.
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  • Running Hyper-V in a lab? Use Snapshots? Check this out!

    The Hyper-V Snapshot feature(Checkpoint in SCVMM) is a very useful feature for Support Engineers. This allows us to revert the VM to a previous state irrespective of the local* changes you’ve made after the snapshot was taken. Working with customers on a daily basis necessitates having a system on which you can mirror the customer’s setup....

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  • How to Use Hyper-V Snapshot Revert, Apply, and Delete Options

    The Hyper-V snapshot feature allows you to capture the configuration and state of a virtual machine (VM) at any point in time, and return a VM to that state without noticeable interruption. When you take a snapshot of a running VM, Hyper-V briefly pauses the VM to create a new automatic virtual hard disk (AVHD) which is essentially a differencing disk, attaches it to the VM to store changes to the VM data, saves the processor state into a file (.bin), then resumes the VM. Hyper-V also makes a copy of the VM configuration file (.xml), and saves the contents of the VM memory into a file (.vsv). Snapshots can also be created when a VM is turned-off, in which case Hyper-V does not need to capture VM memory or processor state data....

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  • Expected Snapshot Merge Behavior for a Highly Available VM

    While working with snapshots that are attached to a highly available VM in a Cluster, you may notice after deleting a snapshot, it does not merge as expected. You'll notice the merge process almost immediately ends and the VM begins to restart....

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  • What happens when a snapshot is being merged? [Hyper-V]

    Ben Armstrong: I would like to now take a little side road to look at what happens under the covers when you delete a snapshot and we need to merge the AVHD.  Imagine that you have a virtual machine with the following snapshots...

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  • Hyper-V Snapshot FAQ

    Ben Armstrong: There have been a lot of questions about how Hyper-V virtual machine snapshots work, and what considerations you need to take when using them.

    Frankly this is an area where I need to do more blogging – and we need to work to make the technology easier to understand “out of the box”.  However – in the mean time our documentation team has put together a handy Hyper-V virtual machine snapshot FAQ that you can read here:

    http://technet.microsoft.com/en-us/library/dd560637.aspx

    This details things like: How are snapshots stored?  What considerations do you need to be aware of?  Why is my virtual machine going into “paused-critical” state? and more.

    <...

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  • Like Snapshots in Hyper-V? - Please read this

    Snapshots is nice to have, in fact very nice to have when running a virtual platform. In Hyper-V it is easy to do snap-shots and there are no problems, or is there something you should be aware of...

    Yes, there is a a issue, it is not a bug but there is something you absolutely need to know, otherwise you will be in serious trouble. So lets here the story... ...
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  • Hyper-V Interview with PMs Part 3 - TAP and VSS Snapshots

    Technet Edge: John Howard, Ben Armstrong, Bryon Surace are program managers in the server virtualization team and give us the technical details on various components of the Hyper-V architecture. In part 3, we dive into the following components: Hyper...
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  • Hyper-V Interviews with PMs Part 2 - VM Snapshots -

    Technet Edge: John Howard, Ben Armstrong, Bryon Surace are program managers in the server virtualization team and give us the technical details on various components of Hyper-V. In part 2 we cover: How virtual machine snapshots work under the covers How...
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