SharedVHDXOne of the new features in Windows Server 2012 R2 is Shared Virtual Hard Disks.

What are the benefits of Shared VDHX?

The benefits of using Shared VHDX on a 2012R2 Hyper-V server is that you can deploy a failover cluster consisting of all Virtual Machines. You can also create failover clusters using Fibre Channel, Server Message Block (SMB) file share, Storage Spaces, or iSCSI storage. The real benefit of using the Shared VHDX is that you don’t have to expose your storage infrastructure like you would with the other options above. This is something that an ISP would want to use because it would be easy to automate the creation of new failover clusters without having to make a new file share or a new LUN.

What does it take to run Share VHDX?

Let me start with the error that many IT Pros see as they start to look at Shared VHDX. If you started to try and use this technology you may have missed some important prerequisites and received this error message:

image

Error Message Error Applying Hard Drive Changes
Failed to modify device ‘Virtual Hard Disk’.
The storage where the virtual hard disk is located does not support virtual hard disk sharing.
Cannot get information for attachment ‘\\Svr01\hyper-v smb storage\shared_disk_1.vhdx’.
The storage where the virtual hard disk is located does not support virtual hard disk sharing.

The common problem here that people run into is that you can’t use local storage (d:\VHDs\disk.vhdx). Further, you can’t use a regular file share (\\Server\Share\disk.vhdx). You either need to have the VHDX file on on a scale out file share or on a CSV volume. The CSV volume can be from iSCSI, fiber channel, SAS, or clustered Storage Spaces with SAS JBODs. So the virtual disk must be a VHDX not a VHD and it must be on Cluster Shared Volumes (CSV) or on a Scale-Out File Server Cluster with SMB 3.01. Again the benefit of using the VHDX file in addition to the storage is that you can add more clusters without provisioning more shares or LUNs and the guests don’t have access to the shared storage. This is easier to secure and automate for you end users who may want fail over clusters from your Hyper-V farm.

Here are the other things that are required to configure a guest failover cluster that uses shared virtual hard disks:

  • At least a two-node Hyper-V failover cluster.
  • Servers must be running Windows Server 2012 R2.
  • Servers must belong to the same Active Directory domain.
  • Availability of configured shared storage resources—for example, CSVs on block storage (such as clustered storage spaces) or a Scale-Out File Server cluster (running Windows Server 2012 R2) with SMB 3.0 (for file-based storage).
  • Sufficient memory, disk, and processor capacity within the failover cluster to support multiple virtual machines that are implemented as guest failover clusters.

For step by step instructions on deploying a Guest Cluster using Share VHDX Microsoft has a great guide on the TechNet site here:

Deploy a Guest Cluster Using a Shared Virtual Hard Disk (step by step)
http://technet.microsoft.com/en-us/library/dn265980.aspx

If you have anything to add – just drop it in the comments!

Thanks –Brian 

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ITEBlog_thumb[1]This post is part of a series of posts by the US IT Pro Evangelist team. In this series we cover, Why Windows Server 2012 R2 is important, how to deploy, manage, configure any number of components in Windows Server 2012 R2. 

This series is deep technical content with lots of How To’s and Step-By-Step instructions. You will learn about storage, cloud integration, RDS, VDI, Hyper-V, virtualization, deduplication, Hyper-v replica, DNS, AD, DHCP, high availability, SMB, backup, PowerShell and much, much more! – See more at: http://itproguru.com/expert/2013/10/windows-server-2012-r2-launch-blog-series-why-win2012r2/