Windows 2012 Hyper-V – The Hypervisor for your Cloud? Part I

Windows 2012 Hyper-V is the hypervisor for the cloud, and VMware’s vSphere is a dead man walking. So declared Aidan Finn at a recent virtualization conference in Hamburg during an enlightening entertaining session which he tastefully entitled, “Windows Server 2012 Hyper-V & VSphere 5.1 – Death Match”.

A bold statement? Hyper-V has often been cited as a “nearly ran”; good enough for the SMB space and smaller Private Clouds, but lacking the muscle for a cloud-focused enterprise. Nice for a visit, wouldn’t want to live there.

A biased statement? Aidan Finn is highly regarded Hyper-v Microsoft Most Valuable Professional and regularly writes on his website about changes and features of the product. In Predicatably Irrational, Dan Ariely dedicates a chapter to the possibility of a fan’s judgement being clouded. And yet, the list of features now available in Windows Hyper-V is compelling. Indeed, back in March we discussed if Microsoft would drive a wedge between VMware and EMC with Windows Server 2012 and Hyper-V.

In terms of embedded services and experience, VMware’s vSphere has a significant place in many organisations’ data centres. Licensing alone is unlikely to change hearts and minds to convert, but what about features?

Can Microsoft claim that Hyper-V is the hypervisor for the cloud? What new features are available in the 2012 release, and how does it now compare to vSphere 5.1. More importantly, will  these changes drive wider adoption?

In this first installment, we take a look at pricing, scalability, and performance, as well as storage.


We’ve spoken before about hypervisor pricing in Licensing your Private Cloud and Microsoft Windows Server 2012 licensing specifically.

Edition Use Case High Level Feature Comparison Licensing Model Pricing  (US$)
datacentre High Density Virtualization Full Windows Server functionality with unlimited virtual instances Processor + CAL* $4,809
standard Low Density or No Virtualization  Full WindowsServer functionality with two virtual instances Processor + CAL*


*CALs are required for every user or device accessing a server directly or indirectly. See the Product Use Rights for details.

The key consideration for those virtualising Windows environments is that there is no licensing for Hyper-V. You license Windows Server the same way no matter what virtualisation you use, be it Microsoft Hyper-V, Citrix XenServer, VMware vSphere, etc. Of course, what happens if you don’t want to license Microsoft machines? Possibly not a thought that often crosses Aidan’s mind.

There is a free standalone Hyper-V server. Although you don’t have any free rights to run Windows VMs, Hyper-V server contains all the features of Hyper-V, including failover clustering.  It doesn’t have a GUI, but it can be remotely managed.

Scalability and Performance

How do the new features of Hyper-V 2012 compare against common competition in many organisations? Hyper-V has much improved scalability and memory capacity than in previous versions, resulting in a far greater capacity to scale to larger workloads.

System Resource Hyper-V(2012) XenServer(6.0)
vSphere Hypervisor
Host Logical Processors (Cores) 320 160 160 160
Physical Memory 4TB 1TB 32GB3 2TB
Virtual CPUs per Host 2048 Undoc’d 2048 2048
VM Virtual CPUs per VM 64 16 8 645
Memory per VM 1TB 128GB 32GB3 1TB
Active VMs per Host 1024 50-1301 512 512
Guest NUMA Yes Host Only Yes Yes
Cluster Maximum Nodes 64 16 N/A4 32
Maximum VMs 8000 800-9602 N/A4 300

1.XenServer 6.0; active VMs per host varies based on Server/VDI workload, with MCS/IntelliCache & HA on/off.
2.Maximum VMs on a Cluster (Resource Pool) on XenServer 6.0 based on a maximum of 50-60 concurrent protected VMs per host with HA enabled.
3.Host physical memory is capped at 32GB, thus maximum VM memory is also restricted to 32GB usage.
4.For clustering/high availability, customers must purchase vSphere.
5.vSphere 5.1 Enterprise Plus is the only edition that supports 64 vCPUs.  All others support 8 vCPUs within a virtual machine.
6.The max number of Virtual CPUs / Host is not documented in the Citrix XenServer 6.0 Configuration Limits documentation.


With storage, Hyper-V has improved its lot and now matches vSphere – albeit with a larger maximum virtual disk size. The stand-out component appears to be native 4KB disk support. The data storage industry is transitioning the physical format of hard disk drives from 512-byte sectors to 4096-byte sectors (also known as 4K or 4 KB sectors). This transition is driven by several factors, including increases in storage density and reliability. So yes, the new shiny hypervisor supports the new shiny feature.

Capability Hyper-V(2012)
XenServer (6.0) vSphere Hypervisor
vSphere (5.1 Ent+)
Virtual Fibre Channel Yes No Yes Yes
3rd Party Multipathing (MPIO) Yes Yes(Manual) No


Native 4-KB Disk Support Yes Undoc4 Undoc4  Undoc4
Maximum Virtual Disk Size 64TB VHDX 2TB 2TB VMDK  2TB VMDK
Maximum Pass Through Disk Size Varies1 15TB 64TB 64TB
Offloaded Data Transfer Yes No No  Yes(VAAI)3

1.The maximum size of a physical disk attached to a virtual machine is determined by the guest operating system and the chosen file system within the guest.
2.vStorage API for Multipathing (VAMP) is only available in Enterprise & Enterprise Plus editions of vSphere 5.1.
3.vStorage API for Array Integration (VAAI) is only available in Enterprise & Enterprise Plus editions of vSphere 5.1.
4.Neither VMware nor Citrix documentation suggest that their respective platforms support 4K Advanced Format Drives.

Hyper-V 2012 the Only Hypervisor for your Private Cloud?

From a scalability and performance point of view, there is much improved in Hyper-V 2012, and the storage improvements have brought the Microsoft hypervisor up to capacity. But besides pricing simplicity, performance improvements, and updated storage what has Microsoft done for Hyper-V?

In the next installment, we’ll expand on the feature comparison and take a look at Security and Multitenancy, Live Migration and High Availability, and backups, and we’ll look to answer if Microsoft can win an organisation’s cloud administrator’s and architect’s hearts and minds.

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11 Comments on "Windows 2012 Hyper-V – The Hypervisor for your Cloud? Part I"

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Great article! When do you plan to write the second part? In the near future I have to convince my boss to continue to use VMware.


Andrew Wood


Should be ready for next week. If you want more in depth information about Hyper-V and Microsoft’s private cloud I’d recommend taking a look at Aidan’s site If you wanted to learn move about HyperV and he was here I wouldn’t tell you that I’d recommend reading his books as he might get all big headed 🙂


Good article Andrew. Interested in reading a balanced article on virtualization/cloud based on facts. Too often, I find this site appears to generally be a vmw fanboy site. We don’t need anymore of that. As an IT manager with real problems (budgets, strategy, resources) I find these sites insulting. My company switched off vmw to Hyper-vR2 a while back (vmw too little bang for the buck) and we’re now deploying 2012/hyper-v3. This release has only solidified that we made the right decision.

Hi, thanks for the article. I do as others have commented seen some VMWare biased articles comparing Hyper server 2012 with vSphere 5. However it is important not to forget the perspective here. When discussing VMWare, pricing has become the sweet point nowdays in the dialog. As most people in the industry working with VMWare knows, most if not all bigger implementations of VMWare are Entereprise or Enterprise Plus editions. This makes sense due to the features they provide. Now don’t forget that many companies (organizations) have negotiated discounts, this should shouldn’t be any surprise for anyone as many Microsoft… Read more »
Hi Andrew, you have made a very extensive list of feature comparisons. One the most important things i believe is vendors reliability and commitment to the customer base when it comes with technology delivery. Microsoft has a bad reputation in that aspect. Very important thing MS lacks is a true vision. They are so slow and so non inventive that they are comparable with commercial IBM products, years behind the cutting edge technology in the labs. The approach you have taken over here is checkbox war, very biased to Microsoft as there is no single No answer or comment on… Read more »
Andrew Wood


I appreciate your feedback. It is fair to say, there is no “no” yet in the right column. There is of course part II which you can comment on (

From your post I’ve realised its a failing of our posting mechanism its not always easy for a series of articles to follow on from – I’ll take that away to the wordpress elves.

There is a similar theme Part II, but who knows what Part III brings…erm besides me.. so far, obviously.

I look forward to your further critique at the end of the series.

Andrew, thanks for clarification this somehow ended up on wrong place it should be on the part two. My comments are valid though, please be more realistic and try to compare apples to apples. Either compare feature by feature, including ones that exist and don’t exit from all vendors which you benchmark (which is a task no man has ever done so far) or differentiate yourself as biased like others do having own disclaimers. I see these series of blogs as truly MS against the rest of Hypervizors, and just the fact that you put the Hyper-V in the first… Read more »


Thanks for a great article. We are looking at moving some of our physical servers to Hyper-V Server 2012 (free) and can’t determine the max number of VMs that are allowed. We understand that if we purchase the Standard version we can run 2 VMs and Datacenter version allows for unlimited VMs. We already own the server licenses on the physical servers that we want to move to Hyper-V Server 2012. Is there a limit on the number of purchased or own licenses that can be loaded and run on the Hyper-V Server 2012 (free)?

Andrew Wood
Standard – 2 VMs, Datacenter unlimited – this is true. It is also fair to say “free” Hyper-V is a windows instance to run VMs. Those VMs must be licensed. “Already own the server licenses”. you don’t make clear what these are. What I do know is, you cannot move an OEM installation to another physical box or host. “purchased/own licenses” not sure at what level that is. Non-OEM volume versions of Windows Server can be assigned to *a* server with a change permitted every 90 days. How that works for you, with the licenses you have? Good question. I’m… Read more »