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The new XenApp template for XenServer has generated a great deal of interest. There have been a several posts about XenApp on XenServer on the Citrix Blog (read Dan Feller's posts here, here, here and here). You can listen to an interview with Dan about this topic as part of the Citrix Delivery Center podcast here.
Recently Laura Whalen in our Solutions Marketing team put together an excellent slide presentation that covers the reasons why you would want to virtualize XenApp on XenServer.
One of the first few slides of the presentation reviews the business case for virtualization based on data from IDC and Gartner. It occurred to me as I reviewed this slide that this might be a good opportunity to add in some slides I recently put together for a different purpose.
A couple of months ago I was asked to give a presentation to some non-technical business leaders in my area about virtualization. As I thought about how to explain to these CEO's and CFO's why virtualization gets so much buzz, it seemed obvious to focus on the costs savings. In my opinion, the server consolidation and costs savings created by server virtualization are a primary driver in most companies first foray into server virtualization. Rapid deployment, high availability and disaster recovery obviously play a huge role in expanding the reach of virtualization, but in my experience the costs savings of consolidation are the biggest initial factor. The ridiculously high costs of energy these days make this costs savings even more important.
After making that decision, I decided to take some data I saw in a webinar by John Humphries of IDC and Simon Crosby of Citrix (archive here) to use as the basis for the presentation to these business leaders.
Of course, a slide presentation full of numbers is no more effective than a presentation filled with technology jargon. I decided to use as many visuals as I possibly could so I did not put the audience to sleep in the first two minutes. I added in numerous stock photos (mostly from istockphoto.com), some public domain pictures from USA.gov and a few photos and screen shots of my own to make a very visual presentation. I have taken a few slides from that deck and added them into the deck built by Laura Whalen.
The template for the other slide deck included a black background. I was not able to get the graphics to work properly in the standard Citrix template (with a white background) without many hours of pixel by pixel editing. I was able to use the transparent re-color feature of PowerPoint 2007 to convert the graphics from Laura's presentation to work with a black background, however.
My Frankenstein presentation creation is embedded below.
(click here to see the presentation in full screen)
Scalability of XenApp on other virtualization products has prevented many from using server virtualization with XenApp. One of the highest priorities after the acquisition of XenSource was to improve this scalability. The new XenApp template does this. You can virtualize the management components of your XenApp farm and individual XenApp servers to gain the availability, management and disaster recovery benefits. We have found that for many resource intensive applications a one vm to physical server provides the best scalability. You can still gain the availability, management and recovery benefits for those servers.
Since there are many notes included with this presentation (mostly from Laura) I have uploaded a pdf of the notes pages (in a zip file to shrink the size a bit).
EDIT: The posts and podcast interview I did with Dan Feller provide much more in depth coverage of this topic. To avoid any confusion, the x64 version of XenApp is recommended for use with XenApp on XenServer. The server utilization number referred to in the slide deck is from an IDC estimate of all servers, not just XenApp servers. As I mentioned in the post and you can see from the documentation provided by Dan, most XenApp servers running applications for users will be the most scalable when one vm is running on one physical server. The cost savings from reduction in servers comes into play with those servers because XenApp running on XenServer is much more scalable than any other virtualization platform based on our testing. That greater scalability will lead to a reduction in servers when using server virtualization. Further, the ability to consolidate license servers, data collectors, and other components offer additional consolidation savings. All of this is in addition to the deployment, support and high availability savings possible with server virtualization.
Edit #2: I have received a few emails asking to see the slides I created for the non-technical audience of business leaders. You can find the presentation "The Buzz on Virtualization" here. This is a very high level overview. One technical person told me it was so high level his grandmother could understand it (I do not think he meant that as a compliment ... ). It did work very well for the audience where I presented it. I like to experiment a great deal with slide design and you can see that in this deck.
What happened to the push for user density with x64? Setting aside the availability-specific benefits of virtualizing a XenApp server, with App Streaming mitigating the need for a comprehensive LMG/Silo based design why pitch increased utilization as a benefit? That slide deck is offering a blatant misrepresentation of average server utilization for a terminal server in a properly architected environment. This is a prevalent issue in the industry in that all the virtualization n00bs run off thinking that virtualizing terminal servers, SQL servers, and Exch servers in the same ratios as their DCs and F/P servers is a best practice. Citrix's failure to properly address this (in an effort to sell XS licenses) is shameful and is leading to a degredation in the overall perception of XA and XS as many places are grossly over consolidating and wondering why their 6 virtualized XA servers run like crap all the sudden on the same piece of hardware that used to host a single physical instance. XA, in a properly designed implementation, should NEVER run more than a 2:1 guest to host ratio unless there are LMG or app/user isolation scenarios where the physical server utilization runs sub 50%. We should be talking about user density per physical device and then delve further into the scenarios where virtualization can offer improvements and benefits beyond the traditional physical server model (mainly workload availability and continuity). I am not saying XA should not be virtualized, but pitching it under the guise of consolidation is moronic on a good day and cuts at the credibility of those positioning it as a benefit. (note: this rant is exclusive of data collectors, xml brokers, and other low utilization Citrix boxen).
The slide deck is designed to be an introduction to the topic, not a comprehensive overview. If you refer to the posts by Dan Feller (and the podcast interview I did with him) that I linked to in the opening paragraph you can get much more detailed information. One thing you would learn from the interview and the other relevant posts is that the recommended version of XenApp for virtualization is x64. I will edit that post to highlight this fact to avoid future confusion.
The 10% utilization number is the average utilization of all servers according to IDC. I highlighted the source for the number in the post and linked to it. I will add an additional statement in the post to avoid further confusion.
In the conclusion I wrote "We have found that for many resource intensive applications a one vm to physical server provides the best scalability." The cost savings from consolidation comes into play with those servers because XenApp running on XenServer is much more scalable than any other virtualization platform based on our testing. That will lead to a reduction in servers. All of this is in addition to the deployment, support and high availability savings possible with server virtualization.
Large XenApp farms usually include multiple data collectors, license servers, terminal services licens servers, xml brokers, and farm metric servers, so in my view the reduction in costs available from server consolidation is very relevant to the discussion. The resulting savings in virtualizing those servers on a large XenApp farm can significantly reduce the overall cost of the project.
). It did work very well for the audience where I presented it. I like to experiment a great deal with slide design and you can see that in this deck. 
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What happened to the push for user density with x64? Setting aside the availability-specific benefits of virtualizing a XenApp server, with App Streaming mitigating the need for a comprehensive LMG/Silo based design why pitch increased utilization as a benefit? That slide deck is offering a blatant misrepresentation of average server utilization for a terminal server in a properly architected environment. This is a prevalent issue in the industry in that all the virtualization n00bs run off thinking that virtualizing terminal servers, SQL servers, and Exch servers in the same ratios as their DCs and F/P servers is a best practice. Citrix's failure to properly address this (in an effort to sell XS licenses) is shameful and is leading to a degredation in the overall perception of XA and XS as many places are grossly over consolidating and wondering why their 6 virtualized XA servers run like crap all the sudden on the same piece of hardware that used to host a single physical instance. XA, in a properly designed implementation, should NEVER run more than a 2:1 guest to host ratio unless there are LMG or app/user isolation scenarios where the physical server utilization runs sub 50%. We should be talking about user density per physical device and then delve further into the scenarios where virtualization can offer improvements and benefits beyond the traditional physical server model (mainly workload availability and continuity). I am not saying XA should not be virtualized, but pitching it under the guise of consolidation is moronic on a good day and cuts at the credibility of those positioning it as a benefit. (note: this rant is exclusive of data collectors, xml brokers, and other low utilization Citrix boxen).