What Is Hyper-V Snapshot [Full Explanation]

Introduction

Virtualization has profoundly transformed the way businesses operate and deliver customer service. Snapshot technology is a crucial aspect of virtualization. Regardless of whether you are well-versed in virtualization or just starting out, it's essential to understand the answer to the question - What is Hyper-V snapshot?

Since Windows Server 2012, the Hyper-V snapshot has officially been renamed to Hyper-V Checkpoints. The change was made to avoid potential confusion between Hyper-V snapshots and VSS (NTFS) snapshots. If you are still using an earlier version of the Windows Server OS, it is also acceptable to refer to these copies as "snapshots." Regardless of whether you call them Hyper-V snapshots or Hyper-V Checkpoints, they serve the same purpose within the virtual machine.

This article will delve into the Hyper-V snapshot technology, explaining its definition, key features, and providing a step-by-step operational guide.

What is Hyper-V Snapshot?

A Hyper-V snapshot represents a point-in-time capture of a chosen virtual machine, preserving the VM's state, RAM data, and hardware configuration at a specific moment. This information is stored within the virtual machine, meaning that Hyper-V snapshots consist of extensive data, such as the VM's configuration settings and the state of the guest operating system at the time the snapshot was taken.

When a user takes a snapshot, it creates a specific point in time for that virtual machine (VM) and offers a straightforward method to revert the system back to a previous state if any issues arise. For instance, you might want to create a snapshot of the VM before installing a new software package. This way, if problems occur, you can roll back to the snapshot. After reverting, the system will be running as it was before the recent software installation.

The benefit of this technology is that we can create Hyper-V snapshots both online and offline without causing issues within a running virtual machine. In Hyper-V, multiple snapshots can be created, deleted, and applied to a single VM.

In the upcoming section, we will delve into several key features of Hyper-V.

Main Features of Hyper-V Snapshot

Below, we outline some key features of Hyper-V snapshots that every Hyper-V user should be familiar with to effectively utilize this technology in their virtual environments. Let's explore them together:

Hyper-V Snapshot File Extension

In fact, Hyper-V Snapshots are stored as AVHD(X) files. When we take a new Hyper-V snapshot in Hyper-V, a new AVHD(X) file will be created. All the data captured at a particular moment are stored in this file. Along with the differencing disk, state files (BIN and VSV) saved by virtual machines, and the snapshot configuration file (XML) are also created. AVHD(X) files are stored in the exact location of the original virtual hard disk.

Once the snapshot is taken, all changes to the data are tracked and stored in the corresponding differencing disk until a new Hyper-V snapshot is created or the older one is deleted. Meanwhile, the original VHD file operates in read-only mode.

Hyper-V Snapshots can be either Standard or Production.

Prior to the introduction of Windows Server 2016 and Windows 10, there was only a standard snapshot available. This kind of snapshot captures the state and memory of a virtual machine at a specific point in time. However, when standard snapshots were employed in production environments, they were found to be somewhat inefficient. To address this, Hyper-V Production Snapshots were introduced. The key feature of Production Snapshots is that they utilize the Volume Shadow Copy Service or File System Freeze to create snapshots of the virtual machine that are consistent with the data. Consequently, Hyper-V Production Snapshots have proven to be highly beneficial in production environments.

Hyper-V Snapshots Are Not a Backup Alternative

Many individuals often confuse Hyper-V snapshots with backup software since they allow administrators to revert the operational state of Hyper-V virtual machines and eliminate software errors. However, this assumption is incorrect. In reality, these are two distinct concepts, as Hyper-V does not offer the same data protection capabilities as dedicated backup tools. The main point is that Hyper-V snapshots necessitate the entire virtual disk to function properly. Consequently, if an interruption occurs at the guest operating system or virtual machine level, the checkpoint becomes inaccessible and unusable. Thus, the inherent architecture of Hyper-V snapshots renders them inappropriate for backup purposes. Hyper-V snapshots serve as a temporary solution to capture a VM's state at a specific moment, but they do not create a duplicate of the virtual disk.

If you're searching for offline backup software that can create a duplicate of your disk, please read the following article:

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Multiple Hyper-V Snapshots Can Form a Snapshot Tree

Snapshots for virtual machines are displayed in the Hyper-V Manager in a snapshot tree, with each virtual machine corresponding to a separate tree. Each new snapshot taken for a VM is added to a new level within that machine's tree. When you select a virtual machine from the list, its snapshot tree appears in the Hyper-V Manager's Snapshot pane. It's important to note that a single snapshot tree cannot contain more than 50 snapshots. You should monitor the state of the Hyper-V snapshot tree to prevent it from growing excessively large, as this can negatively impact VM performance and reduce available disk space.

How to Take a Hyper-V Snapshot on a Virtual Machine

There are multiple ways to create Hyper-V snapshots using either the Hyper-V Manager or the Virtual Machine Connection utility. To take a Hyper-V snapshot, follow these steps:

Method 1: Take Snapshots Using Hyper-V Manager

One method to take Hyper-V snapshots is by using Hyper-V Manager. Here are the steps to follow:

Step 1. Launch the Hyper-V Manager ("Start" -> "Administrative Tools" -> "Hyper-V Manager").

Step 2. Select the virtual machine where you wish to take a snapshot, and then choose "Snapshot" from the context menu.

Step 3. When the snapshot is being taken, the Operations entry for the virtual machine will display "Taking snapshot" along with a percentage value indicating the progress of the snapshot process.

Method 2: Take a Snapshot using the Virtual Machine Connection Tool

You can also utilize the Virtual Machine Connection tool to create a Hyper-V snapshot, which is a more straightforward method. The process is as follows:

Step 1. Open the Virtual Machine Connection tool window.

Step 2. In the window, click on "Action" then select "Snapshot" from the menu options to take a snapshot. Alternatively, you can click on the "snapshot button" located in the toolbar.

Step 3. A dialog will appear during the process, giving you the option to name the snapshot something other than the default name.

Conclusion

Hyper-V snapshots are useful for numerous businesses and corporations when it comes to preserving specific data in virtual machines. Creating snapshots is not a complicated task. It's essential to understand how to use them because the Hyper-V snapshot enables you to revert the virtual machine back to its initial state, eliminating any undesirable configuration changes and updates that have caused issues within the system.