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The Windows Server Failover Clustering feature allows organizations to ensure the availability of applications running inside virtual machines, but it requires central shared storage, which many small and medium-sized organizations cannot afford. In Windows Server 2012 R2, virtual hard disks can be shared between multiple VMs, enabling guest failover clusters without an expensive storage area network. This not only helps organizations save money on storage, but also provides management flexibility.
Windows Server 2012 R2 Hyper-V brings a lot of new features and enhancements. Microsoft's primary focus has been to gain market share for Hyper-V by introducing features that help reduce capital and operational expenses for organizations. For example, Hyper-V Replica and shared-nothing Live Migration both solved common problems and could help reduce overall capital costs. The shared virtual hard disk feature in Windows Server 2012 R2 is another pivotal technology that can help some organizations reduce both capital and operational expenses.
Why do you need the shared virtual hard disk feature?
There are a few benefits of using shared virtual hard disk feature. First, there is no administrative overhead. Since this feature does not require a central shared storage, it can be implemented without additional upgrades to or work on the storage hardware.
Since the responsibility of creating and configuring the shared virtual hard disk settings lies with the virtual administrator, he or she can quickly configure and deploy it without needing to interact with other IT teams which, in turn, improves turnaround time and reduces cost. The shared virtual hard disk feature can be configured in the service templates using SCVMM 2012 R2, which enables the automatic provisioning of guest clusters.
Requirements for using shared virtual hard disk feature
In order to take advantage of the feature, the guest operating system (OS) must be running Windows Server 2012 or later. If you are using Windows Server 2012 as a guest OS, make sure to install the version of Integration Services that ships with Windows Server 2012 R2. The VMBus driver that ships with the Windows Server 2012 R2 Integration Services makes it possible to share a single virtual hard disk with multiple VMs. You will also need to implement the Windows Failover clustering feature on two Hyper-V servers running Windows Server 2012 or later.
The virtual hard disk must be in the VHDX format, and the shared virtual hard disk feature supports both Generation 1 and 2 VMs.
You can deploy a shared virtual hard disk on either block-level based storage or file-based storage. When a shared virtual hard disk is deployed on block-level based storage, the shared virtual hard disk files are kept in a CSV. In a file-based storage approach, the VHDX and VM files are kept in an SMB file-based storage.