About Hyper-V Backup

Backup for Windows features backup and restore of backup and restore of Hyper-V virtual machines and Hyper-V Failover Cluster (BETA) using Shared Volume Storage (SVC).

This chapter covers the following topics:

What Is Hyper-V

Hyper-V is Microsoft's hardware virtualization product. Hyper-V allows to create and run a software version of a computer, called a virtual machine. Each virtual machine acts like a computer running an operating system and programs.

Hyper-V runs each virtual machine in its own space, which allows running more than one virtual machine on the same hardware at the same time.

A Hyper-V Failover cluster is a group of independent Hyper-V virtual machines that work together to increase the availability and scalability of clustered roles. The clustered servers (called nodes) are connected by physical cables and by software. If one or more of the cluster nodes fail, other nodes begin to provide service (a process known as failover). In addition, the clustered roles are proactively monitored to verify that they are working properly. If they are not working, they are restarted or moved to another node.

Hyper-V Failover Clusters also provide Cluster Shared Volume (CSV) functionality that provides a consistent, distributed namespace that clustered roles can use to access shared storage from all nodes. With the Failover Clustering feature, users experience a minimum of disruptions in service.

Failover Clustering has many practical applications, including:

  • Highly available or continuously available file share storage for Hyper-V virtual machines
  • Highly available clustered roles that run on physical servers or on virtual machines that are installed on servers running Hyper-V

What Is a Hyper-V Checkpoint

A Hyper-V checkpoint is a restore point of a virtual machine. Hyper-V checkpoints allow to keep existing states of virtual machines, so in case of any crash, it is easy to roll a virtual machine back to a previous state.

Windows 10 Hyper-V environment is enriched with two types of checkpoints:

  • Standard checkpoints
  • Production checkpoints.

Standard Hyper-V Checkpoint

A standard checkpoint contains a snapshot of a Hyper-v virtual machine, its memory state, but does not contain a complete copy of VM data.

Production Hyper-V Checkpoint

A production checkpoint is a consistent state of a Hyper-V machine. A snapshot of the virtual machine memory state is not taken when using a production checkpoint.

Production checkpoints do not include information about running applications, while standard checkpoints contain the current state of current applications

To learn more about Hyper-V checkpoints, refer to the Work with Checkpoints chapter at docs.microsoft.com

Checkpoint Creation Logic

Checkpoint creation logic in MSP360 (CloudBerry) Backup depends on Hyper-V configuration. The following cases are possible:

  • Production checkpoints are selected
  • Standard checkpoints are selected
  • Checkpoints are disabled (no checkpoint type selected)

CloudBerry Backup always starts by trying to create a checkpoint of the selected type first. In the event of a failure, a recovery inconsistent checkpoint will be created. The recovery inconsistent checkpoint does not contain VM VSS snapshot. If no checkpoint type is set, MSP360 (CloudBerry) Backup starts by trying to create a recovery consistent checkpoint using VM VSS snapshot. In the event of a failure, the recovery inconsistent checkpoint will be created. The recovery inconsistent checkpoint does not contain VM VSS snapshot. In case of the recovery consistent checkpoint usage, I/O activities that are quiesced at a point of creating VM VSS shapshot will be resumed to ensure successful restore. In case of the recovery inconsistent checkpoint is used for restore, the restore may fail.

Hyper-V Machine Backup

The basics of Hyper-V VM legacy backup consist of the following steps:

  • Once a Hyper-V backup plan is run, a Hyper-V host is accessed
  • New checkpoints are created for virtual machines specified in a backup plan. Virtual machines are always backed up sequentially. The new checkpoint is created while a virtual machine is being processed
  • Once checkpoints are read, they are uploaded to backup storage along with required VM configurations
  • As the checkpoint is uploaded to backup storage, it is deleted on a Hyper-V host side. Refer to Hyper-V Virtual Machine Backup (Legacy) for step-by-step instructions on how to create the backup plan for the legacy backup format.

Hyper-V Failover Cluster Backup (BETA)

Starting version 7.4 of Backup for Windows, Hyper-V Failover Cluster backup is supported.

To try the new feature out, download and install Backup for Windows 7.4 (BETA)

The basics of Hyper-V backup consist of the following steps:

  • Once a Hyper-V backup plan is run, a Hyper-V cluster is accessed
  • New checkpoints are created for virtual machines specified in a backup plan. Virtual machines are always backed up sequentially. The new checkpoint is created while a virtual machine is being processed
  • Cluster Shared Volume (CSV) is the only supported shared storage.
  • Once checkpoints are read, they are uploaded to backup storage along with required virtual machine configurations
  • As the checkpoint is uploaded to backup storage, it is deleted on a Hyper-V host side. Refer to Hyper-V Failover Cluster Backup for step-by-step instructions on how to create the backup plan.

Pass-Through Disks

Currently, virtual machines with pass-through disks are not backed up. If such a virtual machine is included in the backup plan, only recovery snapshots are backed up.

As a workaround, you can install another Backup for Windows instance on a virtual machine with pass-through disks and create an image-based backup plan for this VM.

Note that the new Backup for Windows instance requires a separate license