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VMware or Microsoft?– What is a “Purpose-Built Hypervisor”?

How do they REALLY compare?In the first of our articles in the “VMware or Microsoft?” series, I’m going to address some misconceptions and misinformation about what Hyper-V actually is.

In a currently available document that VMware provides, comparing vSphere 5 to the as-of-then beta of what is now Hyper-V in Windows Server 2012, VMware makes the claim that they have a “Purpose-Built Hypervisor”, with “no reliance on a general purpose OS”, whereas Microsoft depends upon the Server OS to be there.

[Insert annoyingly-loud buzzer sound indicating a wrong answer here]

To address VMware’s claim, let’s answer a couple of questions: What is Hyper-V?

“It’s a virtualization hypervisor.”

Right.  And where is it installed?

“On Windows Server.”

[Insert an even more annoyingly-loud buzzer sound indicating a wrong answer here]

Wrong!  It is installed UNDER Windows Server.  (And that’s just one option.  More about that in a sec.)  When you enable the Hyper-V Role on Windows Server, it inserts the hypervisor between the hardware and the host operating system; actually changing the host operating system into just another “Partition” – the operating system running on virtualization that has highest priority and control of the hardware, and the OS you see when you look at the console.  But architecturally, it’s actually running on top of the hypervisor.  And any virtual machines you host are “child partitions”.


(For an even more detailed description of the architecture, read this: Hyper-V Architecture)

“But it still requires Windows Server, doesn’t it?”

[Insert the most annoyingly-loud buzzer sound indicating an incorrect answer that you can imagine.]

NO!  You also have the ability to install use the Hyper-V Server on bare metal, which is just the hypervisor, plus some bits to make it manageable.  And it’s free.

“Ah, free.. so that means it’s not full-featured, right?”

[Insert the SAD TROMBONE sound here, just to mix things up a bit.]

Boy… you’re not very good at this.  The Hyper-V Server is the same hypervisor, with all of the same scale, performance, high-availability (Windows Failover Clustering), flexibility (supporting Live Migration and Live Storage Migration)… everything that’s in the version of Hyper-V installed under Windows Server.

So does VMware really have a valid claim here – that Microsoft somehow has a disadvantage of depending upon a server OS?


[Insert the sound of jubilant trumpets blowing a fanfare of victory and success]

You got that right.

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