You’ve Got to be Kidding Me

Via jtroyer on Twitter, I learned of this post comparing Hyper-V and VMware ESX.

Now, I’ll be the first to admit that I’m a VMware fan, but as others in the virtualization industry know I also recognize that VMware is not a “one size fits all” solution. There are many places where other virtualization solutions, Hyper-V included, may be a better solution for the customer. It really all depends upon the customer’s needs.

That being said, I do have a few questions for the owner of this particular post:

  • It’s a subtle point, but there is a distinction between “free” and “available at no additional charge”. I take vendors to task for this all the time. Hyper-V isn’t free; it’s available at no additional charge.
  • What in the world is “para metal” virtualization? I’ve heard of bare-metal virtualization (the kind that VMware ESX, Xen, and Hyper-V all perform) and paravirtualization (the kind that VMware ESX and Xen can perform; I don’t think Hyper-V does yet). Is “para metal” virtualization a blend of the two?
  • Identical servers are not required in order to support VMware HA. They are required for VMotion. I would strongly suspect that Hyper-V will have similar requirements or will require hardware support like AMD-V/Intel FlexMigration when it’s live migration feature arrives in 2010.
  • Just because VMware ESX can do memory overcommit doesn’t mean you have to use it. It just gives you the flexibility to use it when you need it.
  • I’m sorry, aren’t Microsoft Windows Server 2008, NTFS, and Windows Failover Clustering every bit as “proprietary” as VMware ESX, VMFS, and VMware HA? Am I missing something here?
  • VMware ESX installs just fine on x64 processors from both AMD and Intel. I have four x64 AMD servers sitting in my lab that are happily running both 32-bit and 64-bit guest operating systems.
  • Since when the hypervisor layer not containing any drivers—i.e., having your I/O drivers reside in the parent partition—have anything to do with direct hardware access by the guest OS? Unless I’m mistaken, these two items have nothing to do with each other. And the jury is still out as to whether having your I/O drivers in the parent partition, an approach used by both Hyper-V and Xen, is really a better approach.

Did I miss anything?

UPDATE: VMware blogger Jason Boche has also responded. Good points, Jason!

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  1. vmdoug’s avatar


    You forgot about OS support. I think something was mentioned in that blog that Hyper-V supports more operating systems which I found funny since it doesn’t support NT 4.0 and only 1 flavor of Linux.


  2. Jason Boche’s avatar

    I left my feedback directly on the blog article. I should probably blog it as you have though. We haven’t heard the last of this I’m sure.

  3. slowe’s avatar


    You’re right–I did overlook that part! Although, in looking back at the article now, it looks like he’s trying to talk about who will support the OS. In other words, VMware will only provide Windows support at boot time, whereas Microsoft will support Windows all the time. Well, duh…who would expect one vendor to support another vendor’s software?

    As for the breadth of guest OS support, I would think it is painfully clear that VMware ESX’s support is far more extensive than Hyper-V, but thanks for bringing it up.


    I don’t know if we all need to blog about it, but go for it if you want. Let me know when you post and I’ll add a link to your article here.

  4. DW Hunter’s avatar

    Hi there, I stumbled on this from a random twitter thread.

    On your third point, identical servers are not required for VMotion… with EVC – Enhanced Vmotion Compatibility – allowing non-identical servers and non-identical CPUs in your cluster for vmotion-ing between them.


    are good options. I have implemented this and it works great.


  5. Mike DiPetrillo’s avatar

    I started to think about correcting this but then I just stopped and let the author look like the idiot he really is. This thing is so chock full of wrong points and lies that it pretty much sums up Microsoft’s strategy for winning accounts – lie until they believe you. Thanks for taking the time to write something up about this. Sometimes you run across things like this and just shake your head in disbelief that someone could be so mis-guided.

  6. Andrew Storrs’s avatar

    A few comments Scott,

    - Hyper-V Server is free as is ESXi

    - Should you mention EVC which helps reduce the need for identical servers?

    - You left the “Hyper-V is only 872KB” one all alone… you can miss that one since we all know that a Hyper-V install is closer to 4GB.

    Jason, I’m not sure if your comment will be approved by Mr. Fawzi. Probably a good idea to post them on your blog. :)

  7. slowe’s avatar


    You are correct, but that’s a distinction I didn’t feel like getting into–it can be quite in-depth, and EVC only handles CPUID–it won’t mask applications that don’t use CPUID. As far as I’m concerned, EVC is a migration tool.


    Thanks for the feedback. I’m all about product comparisons, but let’s be sure that they are factual and not fictional.

  8. DW Hunter’s avatar

    Scott, agreed. And, the more I poke around your blog I realize you’ve given EVC some discussion and addressed the CPUID/masking already. I apologize for the “reduandant” post/comment :)



  9. Sven Huisman’s avatar

    Nice respond, Scott! You forgot to mention that ESXi is free. Another thing the guy mentions: with ESX you still have to buy Windows licenses and with Hyper-V enterprise, you can run 4 VM’s on 1 license. The truth is: you can also license a VMware ESX server with a Windows Enterprise license and run 4 VM’s as well. Or license the ESX host with a Windows Datacenter edition and run unlimited Windows VM’s. Microsoft clearly states that it doesn’t mather which virtualization platform it runs on to take advantage of this.

  10. Duncan’s avatar

    It was one of the best blog posts today. I had a lot of fun reading the article, and still burst in to tears even thinking of those parity drivers and the closed shop approach that VMware has going on. MS doesn’t have that closed shop approach, they open up everything!

    No, you are all wrong, best article ever.

  11. Jason Boche’s avatar

    Sven, the licensing/cost thing is a deep rabbit hole of discussion for either side of the table. For either Microsoft or VMware folks to sum up shrink wrap cost and more importantly TCO on 1 line is irresponsible/idiotic and it reinforces how much thought was put into it.

  12. Fawzi’s avatar

    Scoot, I must admit that I am one of your readers and your blog is in my RSS feeds.

    You did a great job in this post I gained some new information about EVC and edited my post using this info

    I am not sure from the info that Sven said “with ESX you still have to buy Windows licenses and with Hyper-V enterprise, you can run 4 VM’s on 1 license. The truth is: you can also license a VMware ESX server with a Windows Enterprise license and run 4 VM’s as well.” I will check that and update you.

    Now I am talking my time to read all points you mentioned in this post and hope that we can discuss any point later

  13. slowe’s avatar


    As I’ve stated on many, many occasions, VMware ESX is a great solution–but it isn’t necessarily the right solution for every single customer. That being said, there are lots of instances where Microsoft Hyper-V may make more sense. (Yes, VMware folks, that’s true even though Hyper-V doesn’t support live migration or Storage VMotion or DRS or DPM…)

    However, it’s critically important that you have a solid understanding of both virtualization solutions in order to make a valid comparison. It would appear that English is not your native language, so some misspellings and incorrect word usage can be allowed, but it would be greatly beneficial to you to minimize that as much as possible, and make sure that you fully understand both solutions. It is in my best interests, even if I believe VMware is a better solution, to understand as much as possible about Hyper-V. Likewise, even if you believe Hyper-V to be a better solution, it would be very helpful for you to more fully understand VMware ESX.

    If I can help further, please feel free to let me know.

  14. Fawzi’s avatar


    Thanks for your kind words. I am doing my best to get better understand for virtualization solutions and of course I will need your help. Thanks again.

  15. Russell’s avatar

    I made it about 3 lines in before I gave up on assuming the guy would know what he was talking about. It’s quite possibly the worst compare/contrast I’ve ever seen between the two products. I’d wager I’ll find a better comparison on than anywhere.

    Surely it is satire?

    Reading through the rest of his blog, he’s basically a microsoft fanboy who doesn’t really understand the core technology (I don’t even think he really understands Hyper-V). It’s like when a child first finds out how something works and he is trying to poorly explain to the rest of the world for a pat on the back.

  16. YC’s avatar

    Hi, Scott,

    The only thing makes 4500 drivers support in hyper-v is Microsoft is “making hyper-v” as client-side hypervisor as well. In that case, you really need those support! Are they doing this?

    Sometime it is hard to argue with people when they are trashing ESX not running on their notebook. The real thing they (and their lab) need is VMware workstation.

  17. Dustin’s avatar

    I’ve added my own response to Fawzi’s website. I’m hoping he responds. Here is my response:

    Hmmm….there are many falsehoods posited here. Many people have already enumerated them.

    Unfortunately, this blog’s technical inaccuracies come at the expense of your credibility. Instead of retaliating at the posters, it might be more credible to refute their points using technical information and fact (notwithstanding ad hominem attacks).

    So here’s your chance:
    1. How much experience do you have with installing, configuring and managing ESX.
    2. How much experience do you have using Hyper-V in a production environment. (Experimental labs used at a company does not count)
    3. Are there any differences in memory management between ESX and Hyper-V? If so, please explain their function and when they actually get implemented.
    4. Are there any networking differences between Hyper-V and ESX. If so, please list them and please describe the advantage/disadvantage to both.
    5. Describe how one would backup a Microsoft Hyper-V environment and how one would backup an ESX environment.

    Assume the latest versions for both ESX and Hyper-V.

    If you can technically answer these questions and sound and rational terms, you’ve got a shot at restoring credibility. I’m looking forward to your response.

  18. Prashant Prahlad’s avatar


    Identical servers are not required in order to support VMware HA. They are required for VMotion. I would strongly suspect that Hyper-V will have similar requirements or will require hardware support like AMD-V/Intel FlexMigration when it’s live migration feature arrives in 2010.

    EVC makes identical servers for VMotion unnecessary, and VMware clearly states how it works. When “other” virtualization vendors say they support(or will support) live migration, it makes you wonder how reliable it would be. For example, Hyper-V’s quick migration has blatant disregard for VM or application stability.

    Look at:

  19. slowe’s avatar


    I agree that feature checks are an important part of any live migration functionality. Given the approach that Microsoft and other vendors have taken with regards to relying upon the hardware extensions to support virtualization–for example, both Hyper-V and Xen REQUIRE AMD-V/Intel VT in order to run virtualized Windows guests–it’s not that far of a stretch to suppose that they will also require hardware extensions in order to support live migration.

    As a side note, though, it’s important to point out that EVC–and AMD-V/Intel FlexMigration upon which it is built–only handle the CPUID feature check. Applications that don’t use the CPUID feature check could still cause problems, even with EVC enabled. At least, that’s my understanding; feel free to correct me if I am wrong.

  20. Nate’s avatar

    Scott, a key point of yours I’d correct is the free vs. no additional charge. Yes there is a no additional charge flavor of Hyper-v with any Windows 2k8, but there is also Hyper-v Server which is a free special purposed server, not a tag onto an existing windows server. It is a specialized OS that is just for doing hyper-v. Comparible to ESXi.

    Even the no additional charge bit is important if you are a Microsoft shop. So you are going to run a bunch of VMs all windows. Well, you are going to buy Datacenter edition so you can run unlimited VMs on your host. You are gong to do that whether you run Hyper-V or ESX. Now if you run Hyper-V you are done spending. If you go ESX you are buying another piece.

  21. slowe’s avatar

    Nate, as you and others have pointed out, it is correct that both Microsoft and VMware offer a truly free option for virtualization–Hyper-V Server 2008 and ESXi, respectively. Both options have limitations, if I am not mistaken, compared to their “for-pay” brethren.

    Of course, acquisition cost is only a component of total cost of ownership (TCO), which is really how organizations should go about evaluating virtualization solutions. For some organizations, Hyper-V may make a lot of sense–that’s fine. For other organizations, VMware ESX will make more sense–that’s fine, too. Only those getting embroiled in a “religious debate” insist that there’s only room for one or the other.

  22. Nate’s avatar

    Much agreed on the TCO avenue. There really is a grander picture of cost including not only the software but hardware, power, cooling, man hours etc. I was just clarifying the point. Yes both freebies as I know it are limited compared to their ‘pay for’ bretheren, nd I don’t believe either is actually marketed as being for prodction use. At least not for enterprise production use.

    I also agree there are different strokes for different folks. Personally I work on Microsoft focused technologies (AD, Exchange, SQL), so I have a leaning towards Microsoft products. A lot of that has to do with what I like to call ‘play nice’ features such as VSS integration. Familiarity with product style and flow as well as shared scripting systems helps too. For other individuals other technologies are going to make much more sense. I can’t imagine a Linux/Unix heavy group deciding to roll with Hyper-V. Now in the storage market I am an iSCSI religious zealot, but that’s another topic :)

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