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Advice on Hyper-V cluster

We've just purchased a SAN solution and want to migrate virtual servers hosted locally on 5 Server 2008 R2 bare metal servers to a hyper-v cluster.

Just looking for a bit of advice. One of the servers will have to serve as a DC to the other 4 cluster nodes. Is it best practice to have 2 DCs in this setup? Also, should I split the 4 remaining servers and create 2 clusters or have 4 nodes in one cluster? I'd appreciate any help/comments.
John Smith
John Smith
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1 Solution
If all five servers are high end servers, you can make all of them hyper-v hosts and part of failover cluster
You must put TWO domain controllers because by having single DC you will face single point of failure
You need to put one DC as virtual instance each on any TWO cluster nodes
Also in DC vm properties select "Always start this virtual machine automatically" in case of unexpected reboot of host.

Its good if you can deploy one DC on physical server but not mandatory

Since you have Five servers, even if you deploy MS Exchange on TWO nodes as VM still you can keep File share witness on any of remaining three nodes to avoid cluster failure

Do not take snapshot of virtualized DC
Also do not forget to keep both DC as primary dns and alternate dns in tcp/ip properties of all virtual \ physical servers

Alternatively you can have Four node cluster depending upon your needs
Let me get this straight, you have 5 physical servers right now that you want to virtualize, and you bought a SAN. You probably don't need a SAN.

What type of Microsoft OS licenses do you have for the existing servers? If you have OEM licenses they are probably worthless if you want to virtualize those environments into a cluster. Windows 2008 R2 Standard from a volume license is a little bit better, but not by much. Did whoever sold you the SAN ask you about licensing Windows in a virtual environment? Microsoft licenses Windows y the physical hardware it is running on. OEM licenses are not transferrable between hardware at all, but they can be virtualized. Volume licenses of Windows 2008 R2 can be moved between hardware, but only once every 90 days unless the source server dies in which case you can move the license again even if it has been less than 90 days.

If you want a cluster, two nodes should be able to handle your 5 VMs. If they can't, add RAM. I run over 50 VMs per host on 5 year old Dell R710 with 8 cores and about 168 GB RAM. At any rate, setup two nodes with Hyper-V Server 2012 R2. You will need Windows 8/8.1 to manage them, or use the free 5-nine Manager. You can virtualize all of your servers onto a 2012 R2 cluster, even all of your DCs. You can't easily virtualize all of your DCs on Windows 2008 R2/Hyper-V Server 2008 R2; I would leave one physical if you use older versions of Hyper-V. Having more nodes in the cluster increases your licensing costs. If you have 5 VMs you need to be licensed for 10 VMs on a two node cluster, but 20 VMs on a four node cluster to run the same 5 VMs.

To run all five of your VMs on a two node cluster, each node needs to be licensed for the maximum number of VMs that it may be running, which is five in case one Hyper-V host is down for maintenance. This requires that each host have five Windows 2008 R2 standard licenses, or some Windows 2008 R2 Enterprise licenses, one Windows 2012 Datacenter license per host, and a different number of Windows 2012 Standard licenses. Below is a summary of how many Windows Server VMs the license for each product is worth. You can add them together to get to the number of licences you need on that host. In your example, if you have one Windows 2008 R2 Standard and one Windows 2008 R2 Enterprise license assigned to a host, that host would be licensed for 1 + 4 = 5 Windows 2008 R2 VMs. Three Windows 2012 R2 licenses would allow you to run 2 + 2 + 2 = 6 Windows 2012 R2 (or earlier) VMs. If you plan on growing, Windows Server Datacenter is great because you can keep adding Windows Server VMs without any incremental licensing cost to Microsoft. As I said, I have over 50 Windows VMs running under a Windows Datacenter license. I keep my server licenses under SA so I can upgrade whenever they release a new version of Windows Server without needing to repurchase licenses.

Windows 2008 R2 Standard - 1 VM
Windows 2008 R2 Enterprise - 4 VMs
Windows 2008 R2 Datacenter per processor- unlimited VMs
Windows 2012 R2 Standard - 2 VMs
Windows 2008 R2 Datacenter per 2 processors- unlimited VMs

You can have Hyper-V FOUR node cluster and keep 1 physical server reserved for backup software to backup your HYPER-V SAN storage and Hyper-V configuration.

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