Virtualization Technology News and Information
Citrix doesn't plan to drop Xen for Hyper-V

Brian Madden recently posted a very interesting piece on his Web site, a prediction of sorts, saying that Citrix has next to no market share, and that it will ultimately drop Xen in favor of Hyper-V.  And the rest of the open source world will drop Xen in favor of KVM.  He writes:

The current market penatration of XenServer is zero. Literally zero. (Sure, some people have bought XenServer, but the percentage of people currently using XenServer is less than the margin of error in all polls asking people what virtualization platform they use. So for all intents and purposes, XenServer's market share is zero.)

But when Hyper-V comes out, this will change. Hyper-V's market share will not be zero for long. Hyper-V will be free and included in all versions of Server 2008. Microsoft has a long history and does a great job creating products that—while technically inferior to competitors—are just "good enough" for people to use them. Especially when they're built-in to Windows.


Microsoft's upcoming Hyper-V product is very similar to the open source Xen hypervisor. The two are so similar, in fact, that I'm now convinced that once Hyper-V comes out, Citrix will shift XenServer so it runs on Hyper-V instead of the open source Xen hypervisor. When that happens, Citrix will have no reason to continue to support Xen.

Meanwhile, there's an upstart open source virtualization engine called KVM. ("KVM" in this context is "Kernal Virtual Machine," not "Keyboard Video Mouse.") Once Citrix (and Microsoft) shift their focus to Hyper-V, we may see the open source community rally behind KVM instead of Xen.

You should check out the entire post, here if you haven't already read it.

Simon Crosby, CTO of Virtualization & Management Division at Citrix, responded on his Citrix blog.  The response is rather long, and I really think you should go read it as well.  Simon writes:

Brian predicts the end of Xen based on the following claims:

  1. Citrix XenServer has "literally zero percent market share"
  2. VMware has dominant presence in enterprises,
  3. Microsoft Hyper-V will take over SME virtualization, so Citrix will abandon XenServer
  4. The open source community will abandon Xen in favor of KVM

His argument is superficially appealing, but unfortunately completely wrong.  That said, I'm grateful that he has highlighted the need for Citrix to clarify its virtualization strategy, and I hope that this long, but rather rapidly prepared response goes some way towards doing so. 

Here is Simon's summary response.


  1. XenServer is growing strongly on its own, and XenServer is inside the industry's most differentiated enterprise virtual infrastructure products from leading vendors.  It offers the greatest price performance, compatibility with Hyper-V, and a rich ecosystem of customer-focused value props for management, availability, dynamism and flexibility.  Get it in your next server, completely built in.
  2. VMware has a strong lead, customer confidence, significant presence, and expensive, over priced products that demand customers buy into a single vendor, proprietary, closed, monolithic architecture that has significant architectural and scalability drawbacks.  Next time your VMware sales guy calls, ask him for some of the free stuff, or better, just download XenServer for free.
  3. Microsoft Hyper-V is a fine implementation of the Xen architecture, compatible with XenServer.  It has a strong development plan.   XenServer today and in the future will extend Hyper-V to address advanced use cases, and to support specific Citrix/Microsoft product partnerships.  A good example is XenDesktop.  There will be others.  System Center VMM is a great product, and will be able to manage XenServer as well as Hyper-V and VMware.
  4. The Xen community is vibrant and growing.   Xen is widely used, massively deployed, core to the product and corporate strategies of some of the industry's largest vendors.  Predicting its demise would be extremely naïve.  KVM is very "in":  interesting, incompatible and incomplete.  The two projects can co-exist independently and happily. 

In this crazy, expanding and changing virtualization world we are in today, both posts are eye opening and good reads.  What is the real future?  Only time will tell, obviously.  But isn't it fun to read predictions, as long as you don't read them as solid fact. 

Read Simon Crosby's complete response.

Published Thursday, July 03, 2008 5:55 AM by David Marshall
Filed under:
RTFM Education » Blog Archive » VirtInfo: Short-Takes - (Author's Link) - July 5, 2008 1:58 PM
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