Win32 APIsĭevelopers can use the SetVirtualDiskInformation, GetVirtualDiskInformation and Quer圜hangesVirtualDisk APIs on the Virtual Hard Disk Win32 API set as documented here. However, the virtual hard drive generated often creates a large amount of data to transfer over the network. This method is easy to use, works for all scenarios and is remotable. Hyper-V will compile the changes into a virtual hard drive and copy the file to the requested location. WMI Exportĭevelopers can export the backup data through the Hyper-V WMI interfaces (as used in the above example). Each has unique advantages and disadvantages. When creating virtual machine backups using Hyper-V WMI, there are three methods for reading the actual data from the backup. Methods for reading backups from WMI Based Backup There is also an example on how to use these APIs available here: This approach is more scalable than using VSS in the host, however it is only available on Windows Server 2016 and later. Instead, a combination of reference points and resilient change tracking (RCT) is used to allow developers to access the information about backed up virtual machines in an efficient manner. This approach still utilizes VSS inside the virtual machine for backup purposes, but no longer uses VSS in the host operating system. Starting in Windows Server 2016, Hyper-V started supporting backup through the Hyper-V WMI API.

However, it is designed for small scale backup operations where all virtual machines on a server are backed up simultaneously. This VSS writer allows developers to utilize the existing VSS infrastructure to backup virtual machines. Hyper-V implements a VSS writer on all versions of Windows Server where Hyper-V is supported. There are several approaches that are available for developers to utilize depending on their needs. Hyper-V allows you to backup virtual machines, from the host operating system, without the need to run custom backup software inside the virtual machine.

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