I have had a very heavy focus on the desktop virtualization space for 12 years and recently even more so in the VDI space. My immediate team and co-workers including sales and technical leaders have been struggling with making recommendations on technology to customers. The topic of VMware View versus Citrix keeps coming up over and over again and it always seems to be FUD and marketing hype. I am so sick and tired of hearing the same old FUD and marketing arguments of why one technology is better than the other. One of my recent encounters was a VMware employee who was actively trying to position VMware View 4.5 over Citrix XenDesktop 4 and XenApp 6 because of how great ThinApp is. It became extremely apparent very quickly that he was reciting marketing bullet points and did not understand the technology well at all. This blog is not going to be extremely detailed but will try to convey why I have made the decisions I have.

Hopefully the next time someone comes to me with some argument about why VMware is better than the Microsoft approach they can present hard evidence or information that I have not heard before and can actually expand my knowledge of the VMware solution rather than immediately recognize it as the FUD that comes straight from the VMware marketing machine. Nothing in this blog is copy and pasted and nothing presented here is anything other than my own wording so please forgive typo’s.


End to End management

– First of all both Microsoft and Citrix have management tools in the product offerings. When you buy the Microsoft VDI suite you get the use of System Center for use within the VDI infrastructure. This suite is simply unmatched as far as I can tell. The VMware guys could take advantage of the same thing but they do not pitch this to their customers as far as I can tell.

Application streaming

– Application streaming is the concept of having your applications packaged up and stored on a server. The application is then streamed to the location where it is run. At runtime the application uses the CPU and memory resources of where it is executed from. This allows the administrators to separate out the application from everything else and give you a better than installed experience.

All three companies offer this ability. That is Microsoft has App-V, Citrix has Application streaming, and VMware has ThinApp. Based on my research it appears that App-V is the most robust of the products or at least most widely deployed and in production use.

So thinking about this if you use VMware view to allow clients to connect to a Windows XP or Windows 7 desktop you must license the operating system somehow probably using Microsoft VDA license. You could easily upgrade and obtain a license for App-V or for that matter you could obtain a license for the VDI suite which would allow you the full rights to System Center and many more things to use in your VMware deployment. This is not the VMware pitch. VMware pitches ease of application management using ThinApp and the pitch appears to be that the app is deployed into the client virtual machine.

There are numerous issues with this. First of all the VMware ThinApp product is not as robust as either the Citrix or Microsoft product. Second of all if you stream the application into the virtual machine you are using the memory and CPU resources of that virtual machine. If I run Microsoft office and load several spreadsheets I need to have enough RAM to support my workload. If I have 30 users all doing this I am allocating that memory 30 times causing my number of virtual machines in a host to be substantially lower. VMware could pitch instead to use session virtualization but they do not appear to be doing this because it is based on Microsoft technology.

Session virtualization

– At the end of the day this is Terminal Servers/Remote Desktop. VMware View can in fact use this but this is not what they lead with in the sales pitch. Let me back up a moment and explain the Citrix and Microsoft approach to application delivery. Ideally as many applications as possibly are packaged using App-V or the Citrix technology for application streaming. These applications are never installed anywhere instead they are streamed into the Remote Desktop/XenApp servers. When the end user launches the application they do so using either the Microsoft Remote App technology or the Citrix technology. In either case once the application launches it looks and feels as if it were running locally. The user could be running the application from home, from a virtual machine hosted in the datacenter, at his corporate desktop, an iPad, a mobile phone, or really on anything.

The key take away here is that the memory and CPU load of running the application is the Remote Desktop server. This server is designed from the ground up to optimize memory and lower the memory footprint. This allows you to run upwards of 100 concurrent users per server. To clarify I am talking about a server that is allocated up to maybe 4 CPU’s and 8 gigs of RAM. You could have several servers on a physical host. The memory footprint used by the Windows XP or Windows 7 virtual machine or end user device could be very low. In fact Windows 7 can run fairly well with less than a gig of memory and run very large spreadsheets using session virtualization. If you are using VDI this allows you to optimize and pack in a number of client operating systems into a single host. Without going any further I submit that the Citrix/Microsoft approach is superior for this reason alone.

Support for Windows 7

– Finally this week VMware supports Windows 7 with View 4.5 before that it was a beta or "Tech Preview". This completely floors me that since the launch of Windows 7 VMware has pitched that you can accelerate Windows 7 deployments with View but the entire time never fully supported it. Finally on Sept. 13, 2010 with their release of View 4.5 it is supported, cannot wait until I hear a VMware rep pitch the Windows 7 support as a major breakthrough.

Windows 7 was released July 22, 2009 and launched on Oct 22, 2009 it took VMWare over a year to support it. Citrix had support for this out of the gate with XenDesktop 4 which was released November 14th, 2009. So supporting it is one thing and using it is another. At this point there is a large install base not just number of license sold but reference accounts actually using the supported technology and it working extremely well.

Along with the release of View 4.5 they now claim to support "Offline Desktop Access" which sounds great. Microsoft has supported Med-V for a very long time now and Citrix has a similar solution. I do believe that the Vmware offline desktop feature was rushed to market but I am open to be proven wrong on this.






Provisioning VM

– With the Citrix solution set you can provision your virtual machines including your XenApp servers with an image. To explain here your virtual machines (Windows 7 and XP or Windows 2003 or 2008) are actually diskless workstations that PXE boot off of the network. They can use a VHD file to boot up then actually and run from this image. In fact they can start up even faster than using a local hard drive. This image can be a pristine image on every boot or a private one that they can be modified such as an assigned desktop.

Provisioning physical

– Just to take it a step further physical systems can also be provisioned in the same way using the Citrix solution. Just to be clear here you can have an environment working very well where even the physical servers and all desktop systems actually boot clean every time off of the network. This means that to eliminate software or virus type of corruption a reboot is all that is required.

Wan optimization and access control

– Although a separate offering using Citrix Netscaler and Access Gateway you can both optimize the WAN traffic and provide secure access to your resources.

Media and audio support/USB/Extra’s

– There is no comparison between the Citrix and VMware solution. With HDX from Citrix and support on WAN or LAN currently supported then upcoming improvements with Windows 2008 R2 SP1 with RemoteFX there is simply no comparison.

Profile management

– While Windows 7 and Windows 2008 and higher systems can take advantage of roaming profiles set by group policy Windows XP cannot. If the company does not already use roaming profiles for the users defining a profile for Windows XP can be very difficult. These issues are solved with the Citrix solution by using Citrix profile management.


– There is no doubt that VMware is the leader in the server virtualization space. In many circles Hyper-V is laughed at. What really amazes me about this is that VMware could be positive and position vSphere as the better more mature product. Instead VMware has taken on a negative campaign and in the process rampantly dispenses FUD and flat out lies. However, for the desktop space even assuming that everything VMware states is true and the gospel it doesn’t even matter because Citrix XenDesktop is fully supported on the VMware’s hypervisor.

Personally I really do like the Hyper-V platform for several reasons one of which being the great support of the System Center Virtual Machine manager which can also manage VMware and Hyper-V. The best thing about Hyper-V is it is absolutely free. If you buy Windows Server 2008 R2 and decide to enable Hyper-V on it then you have to buy the OS but this is certainly not required. The free Hyper-V product fully supports clustering’s and all of the enterprise features you need for the hosts. In reality if you are hosting a large number of servers you will probably want to license it as a Datacenter edition anyway so it being free may not matter.

The one big downside currently for Hyper-V is dynamic memory management but with the release of SP1 it will fully support and in fact it already does in beta. Sorry guys but if VMware says you can accelerate Windows 7 deployments a year before they actually supported it and no-one even called you out on that, in my book Hyper-V does already support this feature at least for anyone still in the decision phase. To be clear here the XenServer product when licensed properly with XenDesktop does already fully include the support so with the Citrix solution this is a non issue.

The end result of the deployed solution set

– At the end of the day the customer may decide that the straight VDI approach is not right for them and that a session virtualization approach (Terminal Server) makes sense. This is the most common deployment type. If this is the case and you purchased VMware View you just wasted your money because for the most part it is a VDI only solution.

This is where the Microsoft – Citrix approach really shines because Microsoft and Citrix together invented Windows desktop virtualization. The Citrix model allows you to deploy the solution in a super wide variety of use cases which is unmatched by VMware, I mean it does not even come close. Therefore I will give in that deploying the entire Citrix suite is harder to deploy than VMware’s complete suite, but sorry guys I take flexibility over limitations any day.

The reality of the situation from my perspective is fairly clear. The VMware marketing buzz is attempting to capitalize on this word "virtualization." The only problem is that virtualization is not all the same and desktop virtualization is significant different than server virtualization. Because VMware is the current leader in the server virtualization space they attempt to make you believe that the VMware View solution is naturally superior. Furthermore the decision to move to desktop virtualization and control is often times being handled by the server virtualization people who may not and often do not understand desktop operating system management strategies.

Citrix and Microsoft have the only enterprise ready suite for server and desktop virtualization including end to end management and monitoring. Without third party add-ons I challenge anyone to successfully argue differently.

Just for icing on the cake and to demonstrate how immature the VMware technology is I am referencing an actual document hosted on the VMware website that states how to integrate VMware into Citrix presentation server remote desktop connection broker. This document is from VM World in 2006.

To top it off recently VMware actually used Citrix to deliver the VMware View training courses this stopped in the last several months.








My point here is not to say VMware’s product is not viable but so far I do not see any reason to deploy it or pitch it as a solution. So far I have not seen or heard a single statement that is not straight marketing FUD that clearly articulates why it is a product anyone should buy. So a large reason for me writing this blog is to simply be able to point someone to it next time this topic comes up (next week) so that we can have a starting point for the conversation. I welcome feedback and comments to





Greg Lirette MCT, MCITP, MCSE, CCA