Partners Websites:

Virtualization Team

TSM Guru Blog



 Virtualization (Last updated: 23-01- 2008)
Citrix Xen Server Enterprise VS VMware Virtual Infrastructure 3


Queries the following Comparison is trying to Answer:


VMware Virtual Infrastructure 3 VS Citrix Xen Server Enterprise

How does Citrix Xen Server Enterprise  compare to VMware VI3?

Advantages & Disadvantages of Xen Server Enterprise & VMware VI3

What is better VMware VI3 or Citrix Xen Server Enterprise? How?

Independent Unbiased Comparison Citrix Xen Server Enterprise & VMware VI3


VMware VI3 VS Citrix Xen Server Enterprise Introduction:


Ok, decided on riding the virtualization boat and confused on the right product for your company. You are in the correct place as here we list the comparisons of most of the virtualization solutions. On this page we will compare the Xen Enterprise & VMware Virtual Infrastructure 3, but other comparisons are available and you can choose them from the menu on the left panel. Below is our unbiased comparison, but we still offer the some what biased comparisons which we has found at the links below


Xen Enterprise VS VMware Virtual Infrastructure 3 (Xen Biased)

Xen Enterprise VS VMware Virtual Infrastructure 3 (VMware Biased)


  VMware/EMC Xen
ITComparison Comments VMware site is a bit easier to guess the name of it and browse in regards of virtualization than Xen site.
Product Name Infrstructure v3 (Starter, Standard, and Enterprise) Xen (Express, Server, Enterprise)
ITComparison Comments Both are doing as good in regards of their naming convention.
Pricing range $1000 - $5750 Free - $2499
ITComparison Comments

This can really be misleading as VMware VI3 you can run a bit more virtual machines on the same specs machine then Xen which make the cost per Virtual Machine almost the same. Never let the initial price fool you.

Primary usage Production Environment

Testing & Development  


ITComparison Comments

Xen is mostly implemented in testing and development

environment in the enterprise today, as it has not been long enough for it to be fully tested comparing to VMware which are mature

enough for production environment.   

Required Host OS (if any) Infra v3:Bare-Metal Xen: Bare-Metal
ITComparison Comments

-: Citrix Xen Enterprise server VS VMware VI3 :-

VMware bare-metal installation harden the security of its product and

   make it independent of any operating system security risks and

 breaches specially in the 3i version, unlike the Xen installation which almost include a full Linux kernal. Therefore Xen will still be affected by Linux bugs and security holes although there not many out there, but still can be of concern to larger enterprise.

Management tools Virtual Center XenCenter Administrator Console
ITComparison Comments

Xen has just released their XenCenter Administrator. Its not as rich as the VMware Virtual Center features wise as its still in its early days, but it do what it meant for and improving quite fast.

Support resources High Medium
ITComparison Comments VMware has been in the market longer, which gave it the chance to build  a huge dedicated professional support. On the other hand Xen are getting the advantage of the Open Source Community backing up their support team.
Supported Guest OS

- Microsoft WindowsNT4.0   


 - Red Hat Enterprise 2.1/3/4


- Red Hat Linux Advanced Server 2.1                                  

- Redhat Linux 7.2/7.3/8.0


 - SUSE Linux Enterprise Server


- SUSE Linux 8.2/9.0/9.1/9.2


-FreeBSD 4.9/4.10/4.11

- NetWare 6.5/6.0/5.1      

- Solaris 10 for X86          

- Vista (Experimental


- Windows 2008 Beta (Experimental Support)       

- Windows 2003           Standard /Enterprise SP1/SP2/R2

64-bit + Virtual SMP (Supported

in Production) 


o Windows Server 2003 Web, Standard, Enterprise, Datacenter SP2


o Windows Server 2003 Web, Standard, Enterprise, Datacenter SP0/ SP1/SP2/R2

o Windows XP SP2

o Windows 2000 SP4

- Red Hat Enterprise Linux (and derivatives (32-bit)): 3.5, 3.6, 3.7, 4.1, 4.2, 4.3, 4.4, 5

- Novell SUSE Linux Enterprise Server(32-bit): 9SP2, 9SP3, 10SP1

- Debian(32-bit): Sarge (3.1), Etch (4.0)



ITComparison Comments

Its obvious that VMware has production support for more OS

than Xen. In addition, Xen requires modification of these OS to be able to perform well. In addition Xen require Intel-VT or AMD-V to be able to run windows platform.


- Higher Performance

- More virtual Machines per hardware

- Almost as high performance in most of our benchmarks for Linux.

- A bit slower performance for Windows.



 Xen is highly depend on Paravirtualization in improving performance and windows are still not Paravirtualization ready yet which is the main reason for lack of performance for guests running windows OS, but Microsoft will be going into that direction starting with Windows 2008

64-bit Support Has full support for most of the 64-bit Operating Systems. Has full support for 64-bit version of Windows Server 2003 Web, Standard, Enterprise, Datacenter SP2
ITComparison Comments Both offers 64-bit Guest OS support.

Live Migration


High Availability


Dynamic Resources






Not Supported

Not Supported



Xen has implemented XenMotion, which is the equivelent of VMware VMotion and seems to perform as well.

HA & DRS are great features that VMware came up with and Xen still does not offer any equivalence as it highly reduce downtime, and balance resources they are still a great advantage of VMware.

Max # of CPUs per Virtual Machine

Max Memory per Virtual Machine

Max Memory per Host

4 Processors





8 Processors







Seems Xen has beaten VMware to this one.
Unmodified OS Can run all supported Operating Systems without being modified

Linux will required to be modified through inclusion of Xen Hypervisor

Windows (Require Hardware Assist).



For Xen to perform near to VMware it need to modify the OS by inclusion of Xen Hypervisor and for windows they are waiting for Microsoft to introduce this concept in their windows 2008. This give a clear advantage to VMware at the moment, but can be a nice integration in the future.
HotAdd CPU in Linux Virtual Machines Not supported Supported



Nice feature, but the affect of it can be matched by changing the share value for the CPU in VMware for both Windows and Linux
Virtualization Approach emulation and binary translation paravirtualization




-: Citrix Xen Enterprise server VS VMware VI3:-

Xen depends on Paravirtualization which requires OS modification by vendor to improve performance by totally forwarding the modified OS instructions directly to the Hardware.

VMware depends on emulation and binary translation which does not require any OS modificaiton and emulate the virtual machines commands.

Special Hardware Requirement Require supported SCSI or SATA controllers. Require Intel-VT or AMD-V



SCSI & SATA controllers has been native to most Intel & AMD servers for a quite bit of time, but Intel-VT and AMD-V are only supported in newer server and will force implementer of Xen to buy newer server, even if they have enough resource on the old one.


Other Related Comparisons:

VMware ESX 4 vs MS Hyper-V R2

Microsoft Virtual Server 2005 R2 VS Citrix Xen Enterprise

Microsoft Virtual Server 2005 R2 VS VMware Virtual Infrastructure 3

Microsoft Windows Hyper-V (WSV) VS VMware Virtual Infrastructure 3.5


Virtualization Comparison Forum:

   Please post your requests, comments, opinion, concern, and read other

   readers comments at our Virtualization Comparison forum.


IT Comparison Index:

   Click here to access our site index at our home page.










Copyright © 2007 ITComparison Team. All Rights Reserved

Contact us:

Please Read our Disclaimer

Call us: 1-800-coming-soon