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.