XenServer and VMware vSphere – A Cost Comparison

I work for a reseller of both Citrix and VMware products.  In many client meetings we often debate over which virtualization platform a client should use for server virtualization and which one is “better”.  Now, if I were to ask all of our engineers (and I have) which hypervisor they would choose (XenServer or VMware) if all things were equal (price, performance, features….) they would almost unanimously say VMware vSphere/ESX.  As we know ALL things are seldom equal especially pricing and this is where the debate gets interesting.

 Usually the statement “XenServer is free which saves us lots of money.  Why should we look at VMware which is much more expensive?” comes into play at some point.  There is no question that this is a very valid point.  So let’s take a look at the two solutions and see where they net out.

First off, the blanket marketing statement “XenServer is free” is, in my opinion, not completely accurate.  If you are just looking for a base hypervisor that will let you consolidate servers, simplify management and perform some other basic feature then yes the “free” XenServer will work, so will ESXi or HyperV.  In fact, you won’t get much argument out of me that XenServer has the most rich feature set of all the free hypervisors.  That being said in most production environments there are going to be certain enterprise level features that you will want and in most cases need, like High Availability and the ability to “vMotion” or move vm’s live between hosts.

For me I see the minimum level of enterprise features being present in VMware vSphere Advanced and Citrix XenServer with Essentials for XenServer Enterprise.  Both of these solutions give you High Availability and vMotion and some other functionality.  So let’s take a look at what each one really costs.  I’ll use MSRP pricing and an environment consisting of 3 hosts.

VMware vSphere                                                                           

Advanced Acceleration Kit (3 servers)                                                                                                    $10,495

Platinum Support (24×7 unlimited)                                                                                                           $2,395

Total                                                                                                                                                                      $12,890


Citrix XenServer with Essentials Enterprise

Essentials for XenServer Enterprise ($2500 each)                                                                              $7500

24×7 Support (5 incidents max)                                                                                                                  $3000

Total                                                                                                                                                                      $10,500

 Difference                                                                                                                                                          $2390


Now, $2390 is still a decent chunk of money but all of a sudden the price gap between the two solutions is not nearly as drastic as $12,890 vs. FREE and this is a much more accurate comparison in my opinion.  Both products are very good and capable of running in a production environment and have similar core feature sets.  You should look at competing products before your spend your or your companies money but in my opinion and experience vSphere Advanced is well worth the extra $2390.  So test them both and you decide. 

So I guess the short answer to “Which one is better?” is the infamous IT answer “it depends”!

In my opinion some things to consider above and beyond price should include:

–          How proven is the solution in production environments?

–          How stable?

–          How easy is it to use and maintain?

–          How scalable?

–          How does it handle backups and DR?

–          General availability of third party products?

–          How well does it integrate with your storage?

Here are a few links to compare products:


http://www.vmware.com/products/vsphere/mid-size-and-enterprise-business/features.html – vSphere

http://www.vmware.com/products/vsphere/buy/editions_comparison.html – vSphere editions chart


http://www.citrix.com/English/ps2/products/subfeature.asp?contentID=1686942 – XenServer

http://www.citrix.com/English/ps2/products/subfeature.asp?contentID=1680964 – XenServer Essentials


23 Responses to “XenServer and VMware vSphere – A Cost Comparison”

  1. John R. Says:


    Maybe I’ve read the pricing wrong – but isn’t VMware’s Vsphere Advanced pricing on a per-processor basis and Citrix’s Essentals is per server (unlimited processors)? If that’s the case, on a 4 proc (multi-core) server which is usually the standard for VM implementations – wouldn’t you multiply VMware’s price by 4? I don’t know of any production VMhosts running on a single processor.

    If this is the case, there is no price comparison at all – and there would be a huge financial incentive to look at Xen over VMware. +$42k vs $2390

    I’m not into the sales/pricing, so I could be wrong; just going by what VMware lists on their product pricing page here – http://www.vmware.com/files/pdf/vsphere_pricing.pdf

    What are your thoughts?


    • bcalfo Says:

      Sorry, I should’ve been more clear. The VMware Advanced Accelerator Kit includes licensing for 6 processors (3 servers)and for vCenter. It is not a per processor cost of 10k. Thanks.

  2. John R. Says:

    Oops, already found a math mistake. It’s more along the lines of $42k vs $10,500. Not quite as dramatic, but it’s still 400% higher.

  3. Matt Taylor Says:

    Great post Brian. I would like to emphasize the difference in support that you pointed out. Citrix gives you 5 incidents only while VMware is unlimited. It’s not easy to google and find solutions to common XenServer problems. I can see someone eating through those 5 incidents fairly quick. To me, that helps narrow that price margin even more.

  4. ThomasB Says:

    Not sure whether comparing XenServer Essentials Enterprise and vSphere Advanced is really valid, as the Essentials Enterprise Edition includes much more features. Have a look at this white paper for a more detailed comparison: (http://citrix.com/site/resources/dynamic/salesdocs/XS_vs_VMware.pdf)


    • bcalfo Says:

      Thanks for the link Thomas. Essentials Enterprise and vSphere Advanced are the lowest entry points to get both vMotion and HA functionality out of both products. Above and beyond that each product has some functionality that the other does not, VMware Fault Tolerance for example. This link is a whitepaper from Citrix so it will definitely have a slant toward their product but good information none the less. Thanks again.

      • JC Says:

        Hi, The vmotion on Xenserver is free of charge you don’t need the essential package for that.

      • bcalfo Says:

        Agreed, however HA is not part of the free product and requires Essentials.

  5. John R. Says:


    Could you give an updated cost comparison showing 3 servers with 4-processors in each? I think that would be a more typical scenario for a virtual host. I personally don’t know of anyone implementing dual-proc servers for VM hosts in an enterprise implementation.

    It would also be interesting to see where Microsoft Hyper-V fits in when you add management/HA features.

    • bcalfo Says:

      I’ll see if I can put something together in the next week or two. XenServer is licensed up to 4 cpu’s so if you are using 4 proc servers the pricing will definitely be better. Almost all of our clients use dual quad-core processors in their ESX hosts.

  6. Rob A. Says:

    Microsoft Hyper-V Server 2008 R2 is free with high availability and with Live Migration. There’s also a public comparison here:


  7. Ron Kuper Says:

    Live Migration (AKA vMotion or XenMotion) is FREE with XenServer.

  8. Jef Riechers Says:

    Couple of points.

    1> Processor count definetly matters. More then 2 sockets per box and VMWare jumps far above Xen.
    2> My clients that have purchased xen support contracts have only used 1 incident so far. All other questions have been answered on support.citrix.com.
    3> Windows Licensing. VMWare requires the VI server to handle motioning, ha and centralized administration. And this is usually a physical box that people often forget about pricing in their designs.

    • Michael Colson Says:

      A Windows license will also be required in the XenSever solution if Workload Balancing is going to be used.

      • Jef Riechers Says:

        Yes, but again that was outside the realm of discussion here for basic HA.

        It’s just a fact:
        VMWare is more expensive for it’s licensing, for MS Licensing, and for Hardware purchases then XenServer.

  9. John R. Says:

    Just my 2 cents, but I think VMware will always be a ‘premium’ product. That’s not a bad thing, as long as the benefits match the value. I think that in the end, everyone will benefit because VMware will have to stay competetive somewhat in pricing if they want to keep their market share.
    It’s also pretty obvious to see that the stiff competition is driving innovation among all the players in this space which will again be to everyone’s benefit.
    Some folks are going to use VMware because of it’s track record, performance and large enterprise footprint. Some folks are going to be using Xenserver, Hyper-V and (insert others here) because they feel that it gives them a better performance/value. I think there are cases to be made for both, especially with the shrinking gap in price/performance.
    If I’m putting in a new VDI infastructure (yes, that’s redundant) and the client already has VMware in place, it would be foolish to try and propose to replace that existing infrastructure. On the other hand, if my client was all about lowering costs while still providing performance/stability, it might definitely be worth everyone’s time to present them with a Xen/Hyper-V alternative. If Citrix matches VMware’s support pricing models I can see a lot more people taking a close look at Xen.

  10. Gottfried Matthew Says:

    A cost comparison can done on various idea’s in mind. Obviously looking at licensing and support cost is one way to compare both solutions.
    However would it not be fair to look at what hypervisors are “producing”? Hypervisors are running virtual machines – therefore customers might like to know, how many virtual machines are supported by a hypervisor. The calculation is simple: If I need more servers using hypervisor A to run a specific number of virtual machines, I might get a different result in the comparison.
    And there are a couple of publications, which are trying to demonstrate that ESX runs more VM’s than XenServer – assuming identical hardware. Those publications are documenting up to two times more VM’s on ESX than on XenServer – which could basically double the calcluated costs for XenServer.
    I am not saying that calculating the cost for a VM is the ultimate correct way to compare costs of hypervisors – but I wanted to show, that a comparison of license and support does also not articulate the full truth on a cost discussion.

  11. Jef Riechers Says:

    On number of VMs per virtual server. Yes, I have see that with memory overcommit VMWare has been able to show that they can fit more VMs per box.

    But I haven’t seen anyone show what the “cost” of that is. Mainly, what of the performance degradation by cramming virtual machines on a piece of hardware.

    And from what I have been seeing with the newer hardware the cost to double or triple your ram is still less expensive then memory over commit.

    Have there been studies that speak of this?

  12. SHenson Says:

    One thing to keep in mind when comparing 4 physical processors to 2 physical processors, is today I can purchase the HP G6 line with the new Intel processors. These servers out perform the 4 physical processor servers. Come Jan/Feb when the new Intel processor is available for the 580 series servers, then utilizing these servers become more of a factor in the comparisons. My only fear with the 4 physical processor servers is the back plain may not be able to handle the amount of through put the Virtual servers can create. It all comes down to bottle necks and what your application determines to be that bottle kneck. Also keep in mind a feature to feature comparison is always needed. The challenge I have with XenServer is that all like features for VMWare are new, or coming soon. They are always playing catch-up and never the leader of the pack. Also some of their feature sets to make them comparable are 3rd party add-ons. So remember when looking at support, you don’t have one throat to choke, you will be playing the pointing game when it comes to troubleshooting issues.

    • Roger Klorese Says:

      Actually, Citrix has pioneered several features that VMware doesn’t have or is playing catch-up with. Among them:
      – intelligent storage integration (goes back two years in XenServer, just barely showing up in vStorage APIs)
      – dynamic provisioning (only somewhat approximated via linked clones in vSphere 4, delivered in provisioning services in Platinum since early 2008, now in Enterprise too)

      Besides, the biggest laundry list of features is a diminishing-returns game. Delivering the features people actually need and use, at a fraction of the cost, is the path we’re going to stay on.

      • Roger Klorese Says:

        And, by the way, the only feature you can identify that people use that is a third-party add-on is fault tolerance — which a small fraction of workloads require. High availability, workload balancing, lab management, stage management — all are sold and supported by Citrix.

  13. William Gayle Says:


    I’d like to give my .02 cents and in the end that might be all it’s worth. I’ve actually been using the XEN hypervisor included in SLES11. I also have been testing Novell’s SLES11 High Availability Extensions year subscription costs retail $700.00 per year unlimited email support with escalation to phone if server is down. Live migration and using LVM for snapshots are included in the SLES11 so live backups are available without pausing the vm’s and it also includes live migrate but this is not high availability. The HAE includes cLVM LVM for clustering, DRBD which provides block level raid1 between nodes, openais and pacemaker the cluster resource manager, it also includes OCFS2 as the clustered filesystem to allow for a primary/primary configuration.

    Once you combine these capabilities it gives a truly high available system it monitors stops/starts vm’s in the cluster with no user intervention. I can do live migrate between nodes as well recent studies shows heavy work loads are best on the Citrix XEN and disk IO is better on Novell SLES XEN the only time VMware out performs is when one over subscribes hardware which is not a problem with most new implementations.

    There are many options but for cost and performance I see none as good as this right now. The other thing is if you need the next level I personally think none of them can hold a candle to Platespin which Novell now owns this does everything and anything more cost effectively than Citrix or VMware and can manage VMware, XEN and Hyper-V allow the management tool to be used if hypervisor direction ever changes in ones environment.

    Let me know if you think I’m way off base with my post. I like to get opinions.


  14. Mike Says:

    “Some folks are going to use VMware because of it’s track record, performance and large enterprise footprint.”

    And some folks will never consider another product and prefer to stick with what they know. Its a fact of life, Windows vs Mac vs Linux or EMC vs HP SAN’s and so forth. Yet those same comfort zone folks will post how “their” ‘comfort’ product is vastly superior without even cracking the lid on another product.

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