Hyper-V backup best practices you'd do well to remember

You’ve probably backed up your physical datacenter plenty of times, and it’s all gone off without a hitch. Some applications might have had special considerations, but in the end, the backup process as a whole was a smooth affair and no, this has nothing to do with a Diane Lane/Richard Gere movie.

The problem starts when you’re dealing with a virtual datacenter. Several new factors come into play, such as volumes, host data, disks, domains, and services, and you need to come up with a good plan to keep the backup process of your virtual machines robust and simple. As the complexity level increases significantly, more planning needs to be done for a safe and efficient backup of your virtual servers and data. It is for this reason that we’ve put together a list of the best Hyper-V backup practices.

Never install other applications or roles on your Hyper-V host

Hyper-V host servers should have one function only – to be the host server. You should not make the mistake of treating them like a file server, an application server, or a Domain Name System (DNS) server. If any data and software exist that are not related to Hyper-V, you should place them in a different physical server.

This step is important to retain the stability of the host server and keep host level backups simple. Otherwise, the tiniest of problems with an application or a role on the Hyper-V system can impact all the virtual machines (VMs) and the services they offer (no, they cannot make you some donuts).

Every virtual machine must be assigned a single application or role

You must assign only one application or role to each Hyper-V virtual machine. You will find that the process of making guests is simple enough, and the dedicated environments help with the task to a significant extent. A dedicated environment means that your server has a partition dedicated entirely to running your business apps.

When a single application or role is assigned to each guest, backups become easier. You have complete control over the way services and guests are recovered, and allocation of backup licenses and agents is no longer a hassle.

Significance of guest only Hyper-V backups

The Hyper-V host server offers the architecture, processes, and platform needed to support and handle your virtual machines. Even though backups of the whole physical server are welcome, you will find that backing up just the guests can prove useful as well. This is because they contain all the data you require and don’t need much space.

Always allow Hyper-V integration services

Volume Snapshot Service (VSS) is technology that enables you to take automatic or manual backup copies or snapshots of computer volumes and files, even while they’re in use. These snapshots may be used by backup software to maintain copies of data that have changed at the time of the backup.

This would mean that all the backup data reflects the data as it was at a particular point of time – a method known as crash-consistent. On the other hand, application-consistent means that a VSS-aware app checks its own files within the VSS snapshot to ensure their validity.

Never use the guest for backup, always pick Hyper-V host server

Protecting your Hyper-V guests is easy. All you need to do is install your backup software on the physical server and then use it to back up the guests. This makes it simple and easy for you to back up numerous guests in a single backup session. Moreover, the guests stay in a single backup, which saves time and effort during recovery. You also manage to save money since this only requires one backup license. In some cases, a backup agent might be required but they can work on a single host license.

Never Backup a CSV device directly

Cluster shared volume (CSV) indicates a shared volume across different hosts. If a CSV is used by your guests, the volume must never be backed up directly as the VSS writer on the Hyper-V server will not be involved. The Hyper-V server needs to be backed up so that the VSS writer is able to make backups of data on the CSV that remain consistent throughout various applications.

Backing up the entire volume

If you’re performing the image backup of your Hyper-V volume, then you should try to back up the entire volume. This helps improve the performance of the image backups, and increases the speed.

If the entire volume is backed up, it is critical to have your VMs on a separate volume so that they can be excluded from the backup. If guest files or guest categories get mixed up across volumes, the backups tend to increase in complexity and become less efficient.

Use separate volumes for guest data and system data

You should never store Hyper-V guest data onto the volume where the Microsoft Hyper-V Server was installed. The same rule extends to the physical server’s operating system. It is recommended that virtual machines have their own volumes, and those volumes should not contain system files of any kind. Not only does this improve the performance of your system, but it also helps remove any conflicts.

Make use of fixed virtual disks

The performance of your Hyper-V host server and the integrity of your data – both of which are necessary for backups – are affected by the kind of disks you use. It is exactly for this reason that your Hyper-V host server needs to use fixed virtual disks. You might be wondering why dynamic and differencing disks and pass-through disks don’t work in this context.

Pass-through disks make the whole system unnecessarily complex and never allow guest snapshots or Hyper-V replica. On the other hand, dynamic and differencing disks include performance and space overhead, which affects the overall performance of your system. When you use fixed disks, you are certain of better data integrity and performance. Your backups become better as a result.


Now you can rest a little easier, but do not ever become complacent. The Cleveland Indians became complacent in the 2016 World Series and they ended up losing to the Chicago Cubs. Not good for the Indians! Or for you.

These best practices are all fantastic when it comes to managing your Hyper-V backup process in a proficient manner. They standardize the backup procedure and are designed to deal with different failure scenarios. They are extremely useful in bringing up the guests fast in the event of failure. And you never know when something is going to fail.

Photo credit: Pixabay

Benjamin Roussey

Benjamin Roussey is from Sacramento, CA. He has two master’s degrees and served four years in the US Navy. His bachelor’s degree is from CSUS (1999) where he was on a baseball pitching scholarship. He has an MBA in Global Management from the Univ. of Phoenix (2006). Currently he lives in the Phoenix area after living in Cabo San Lucas, MX for 3 years. He enjoys sports, movies, reading, and current events when he is not working online.

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