Part 7 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Cluster Shared Volumes

In previous steps, we have completed the following:

-2 Windows 2008 R2 Hyper-V servers (LAB-HVCORE-01 and LAB-HVCORE-02)
-Attached to a couple of 300GB iSCSI LUNs hosted on EMC Storage.
-Created the initial External virtual network on each Hyper-V host using Hyper-V Manager.
-Run the cluster configuration validation wizard
-Created the Windows Failover Cluster
-Created the Failover Cluster Quorum

Here are the links to the previous posts:

Part 1 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Install Hyper-V and Failover Clustering
Part 2 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Configuring iSCSI Connectivity
Part 3 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Hyper-V Virtual Networking
Part 4 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Cluster Validation Wizard
Part 5 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Build the Windows Failover Cluster
Part 6 – Creating a Windows Server 2008 R2 Hyper-V Failover Cluster: Creating the Cluster Quorum

In this step, we will enable and configure Cluster Shared Volumes. CSVs represent a vast improvement in the way storage and virtual machines are managed, the benefits (as seen on Microsoft TechNet) page are shown below:

• Provide support for Live Migration, moving VMs between Hyper-V hosts with no server interruption. (Similar to VMware VMotion)

• You can reduce the number of LUNs (disks) required for your virtual machines, instead of having to manage one LUN per virtual machine, which was previously the recommended configuration (because the LUN was the unit of failover). Many virtual machines can use a single LUN and can fail over without causing the other virtual machines on the same LUN to also fail over.

I have seen cases where one LUN per virtual disk had been used.

• You can make better use of disk space, because you do not need to place each Virtual Hard Disk (VHD) file on a separate disk with extra free space set aside just for that VHD file. Instead, the free space on a Cluster Shared Volume can be used by any VHD file on that volume.

• You can more easily track the paths to VHD files and other files used by virtual machines. You can specify the path names, instead of identifying disks by drive letters (limited to the number of letters in the alphabet) or identifiers called GUIDs (which are hard to use and remember). With Cluster Shared Volumes, the path appears to be on the system drive of the node, under the \ClusterStorage folder. However, this path is the same when viewed from any node in the cluster.

Cluster Shared Volumes do not need to be assigned a drive letter!

• If you use a few Cluster Shared Volumes to create a configuration that supports many clustered virtual machines, you can perform validation more quickly than you could with a configuration that uses many LUNs to support many clustered virtual machines. With fewer LUNs, validation runs more quickly. (You perform validation by running the Validate a Configuration Wizard in the snap-in for failover clusters.)

• There are no special hardware requirements beyond what is already required for storage in a failover cluster (although Cluster Shared Volumes require NTFS).

• Resiliency is increased, because the cluster can respond correctly even if connectivity between one node and the SAN is interrupted, or part of a network is down. The cluster will re-route the Cluster Shared Volumes communication through an intact part of the SAN or network.

Enabling Cluster Shared Volumes is as simple as launching the Failover Cluster Manager and clicking Enable Cluster Shared Volumes as shown below:

Use the Failover Cluster Manager to add CSV storage:

1. Within the FCM MMC, click Cluster Shared Volumes on the left-hand pane and on the far right-hand pane, under Actions, click Add Storage.

2. On the Add Storage window, specify the Cluster Disks/LUNs to be used a Cluster Shared Volumes and click OK.

**I’m sure you’ll notice these disks have drive letters assigned to them. That is due to the fact that, when I built this lab, I was unaware that the drive letters were unnecessary.**

3. The Add Storage wizard finishes and the new CSVs are displayed:

CSV volumes are stored as directories and subdirectories beneath the ClusterStorage root folder, which typically exists on the root of C: to provide a consistent file namespace to all Hyper-V cluster nodes. This ensures any VMs stored on a CSV have the same name and path from any cluster node. In this example, the CSV volumes (Volume1 and Volume2) are stored in the ClusterStorage folder on the root of C:, thus, the fully qualified path to each of the CSV volumes will be:

C:\ClusterStorage\Volume1\
C:\ClusterStorage\Volume2\

When you build a virtual machine, install into a CSV (in this case, I made a subdirectory called XD-DDC to hold a XenDesktop Delivery Delivery Controller) and make it highly available in order to support Live Migration.

Well, I think we’ve reached the conclusion of this series. Windows 2008 R2 Hyper-V is certainly a step up from Windows 2008 and can be an attractive server virtualization alternative, in my opinion for smaller businesses that may never support or require more than a couple dozen servers. However, Hyper-V’s feature set still falls short when compared with VMware vSphere, the standard for server virtualization.

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