Hyper-V and VMware different virtual machine backup strategy

Windows Volume Shadow Copy Service VSS helps ensure the implementation of virtual machine backup strategy by ensuring data consistency from virtual machines at a certain point in time.

For a successful virtual machine backup strategy, only Windows VSS is not enough. Powerful virtual machine backups need to work with physical hosts and various other components.

If it is a complex situation, such as having different hypervisors and backup methods requires a wide range of different architectures. Let's take a look at the differences in virtual machine backup strategies on Microsoft Hyper-V and VMware vSphere platforms.

Coordinating Hyper-V Virtual Machine Backup

Virtual machine backup is of course a highlight of Hyper-V. Having the same operating system on both the host and the guest, as if Hyper-V is all on Windows, this is quite beneficial for virtual machine backup strategies. Under this architecture, Windows VSS is naturally installed on the host and each virtual machine, making host-level backup more convenient. The host also has a Windows Server Backup application that acts as a VSS responder. You can even install third-party products to support virtual machine backup strategies.

Backing up Hyper-V virtual machines requires coordination between the Windows VSS instances of the host and the child. So the Hyper-V integration component installs code for each virtual machine. This code allows Windows VSS writes on the host and communicates with any registered VSS Writers running in the virtual machine to match the inactivity. This stack of VSS instances ensures that the application is successfully quiesced as a backup of the virtual hard disk files.

VMware Virtual Machine Backup Using Windows VSS

VMware vSphere uses a different architecture than Hyper-V, which means that Windows VSS is not part of its management. At the host level without Windows VSS, snapshots and still activities must be controlled by some other service. For VMware virtual machine backups, use VMware Consolidated Backup or the latest vStorage API.vSphere Data Recovery feature is another option.

Like the Hyper-V Integration Component, vSphere requires a special device to add the VSS Requestor component. It is part of VMware Tools.

The implementation benefits of VMware's VSS Requestor raise additional concerns: Any virtual machines previously created in vSphere 4.0 require additional configuration to support application consistency. The eleven steps required for this process are discussed on page 38 of the VMware Data Recovery Administration Guide. The process involves enabling the UUID attribute disk.enableUUID in the virtual machine configuration parameters. Virtual machines created in vSphere 4.1 do not require this extra configuration.

If these additional steps are not completed in a successful virtual machine backup strategy, the virtual machine may recover using inconsistent application data. Just as the lengthy database validation process caused a sudden need for power cables from the Exchange server, restoring inconsistent data is not what we need.

Third-Party Tools for Virtual Machine Backup Strategies

There are many third-party tools integrated with Hyper-V and vSphere for virtual machine backup and recovery. Some people take this orchestration process step as a further step by automatically inserting the agent into the virtual machine backup.

This agent makes the recovery process easier by ensuring that the Active Directory Domain Controller is always restarted in non-authenticated mode, for example. Some extra steps are required to successfully recover, but if the agent does not appear when the virtual machine is started, it will fail.

Coordinating virtual machine backups with the relationship between Windows VSS and the host is not as simple as it seems. Especially for business-critical applications, many components of a virtual machine backup strategy must be integrated if the virtual machine is to be properly restored.
Author: Greg Shields Translator: Tang Qiongyao