VDI versus Terminal Services #VD3261
On Thursday September 18, 2008 I was lucky enough to be in the audience for Brian Madden’s first ever VMworld Session. As a well known Citrix administrator and a popular blogger, Brian’s opinions and recommendations regarding Citrix, Microsoft Terminal Server, and Server Based Computing (SBC) in general are followed worldwide. With the audience overflowing the Ballroom D of the Venetian Hotel / Sans Expo Conference Center, Brian provided a thought provoking, entertaining, and often times humorous presentation comparing the pros and cons of Virtual Desktop Infrastructure (VDI) and Terminal Services (TS) today. Then Looking forward, Brian analyzed the future of SBC and rationalized the potential of VDI. I would have to rank this session as one of the best that I have personally attended at any of the three VMworlds I have been to.
To get a feel for Brian’s presentation style, watch the footage Eric Sloof shot and now provides In streaming video from his NTPRO.nl blog site. Eric has spliced together roughly 17 minutes of the 1 hour presentation, but it is still worth watching in conjunction with reading my notes that I have provided in the rest of this post.
Brian started out by likening Terminal Services to the
conservative, corporate accepted standard “right way to do things” and VDI as the modern, young and alternative youthful approach to SBC. Referencing a debate style session from the Briforum held in Chicago earlier this summer, Brian’s slides showed photos of Bernhard Tritsch in a business suit as Terminal Services while photos of himself in jeans and a t-shirt as VDI. Using a debate –like approach, Brian listed the advantages of each.
Advantages of Terminal Services
- Proven technology with over 80 million users
- Cost effective
- Reliable solution
- Enterprise technology in use for more than 10 years now
Advantages of VDI (M.A.P.S.)
- Centralized management as all desktops images are in the data center
- Ability to access the desktop from anywhere (internal and external on many devices)
- Great performance of low speed bandwidth
- Better data security
Brian then pointed out that the M.A.P.S. acronym used to represent the features of VDI today is the same as what was used to describe the advantages of Citrix Terminal Server 10 years ago. He concludes this portion of his presentation by saying that TS and VDI are both SBC, and M.A.P.S. really describes the advantages of SBC.
Brian then listed some disadvantages of SBC today.
- Can only be used when online
- Display and media protocol limitations
- Not all applications are compatible
- Lack of user personalization
Brian explained that both TS and VDI are being used for SBC today, and very often together. He made points such as offline applications still require local installs or streaming, laptops still require operating systems, and some applications are just not worth integrating. I believe Brian was setting up some cases where VDI will out shine TS in future implementations.
Getting back to the specific VDI versus TS debate, next Brian listed some pros and cons of each technology and factors that make each solution unique.
Yay for TS!
- Great user density ($ per user)
- Application thin provisioning – not to be confused with storage thin provisioning, Brian is referred to the ability to install an application one time for many users
- Mature technology with a full ICA feature set
Boo for VDI!
- Disk space needed
- Management nightmare for large user deployments
Desktop problems are the same
- Must support user errors
- Must maintain desktop licenses
- Must patch desktops
- Can’t use the desktops offline
Yay for VDI!
- Live migration of running desktops
- VM suspend and resume capabilities
- Better load balancing
- Today there is actual competition among VDI vendors
Brian also listed 2 other pros in the “Yay for VDI!” segment that he immediately disagreed with as unique factors and then offered an explanation why.
- All users can be admins – disputed as a uniqueness of VDI because of “it’s not a smart idea” and supportability challenges
- Non TS applications can run – disputed by the fact that most applications that can’t be run in TS are really not SBC applications anyways
Curiously, Brian did not have a “Boo for TS!” list.
The second half of this presentation focused only on VDI as the solution for SBC moving forward. Brian discussed the fact that many companies are now providing VDI solutions. He showed a slide that listed several companies that I was not aware that they even had a VDI offering.
Who Do You Use for VDI?
- Quest / Provision Networks
- Red Hat / Qumranet
In one of the more humorous moments in his speech, Brian pointed out that Microsoft was not in the list of VDI providers. After asking the question “Where is Microsoft?”, he quipped “Well, they are in 1989 with regards to licensing!” Brian’s point for this comment was that even though Microsoft is currently “digging in their heals” with their licensing, they will eventually have to change their licensing to match a VDI user based desktop delivery model. For today Microsoft is content with providing the Hyper-V infrastructure for virtual desktops and allowing the complete VDI solution be provided by others.
Brian concludes by talking about the future of SBC, and how he believes VDI will begin to replace TS. He explains that are key challenges VDI must overcome first to make this happen.
- User Density (measured in $ per user) – this is simply the ability to host more desktops per virtualization host than possible today. Citrix has this unique advantage now, but with advancements in technology and hardware (streamlined operating systems, 6 and 8 core CPU servers and larger amounts of memory) VDI can surpass TS in the future.
- Remote display features – future remote display protocols and virtualization assisted hardware will create video, 3D and media advancements for virtual desktops of the future
- Application thin provisioning – using a master template desktop VM to deploy many VMs as linked clones is a feature already available today that solves this challenges. Citrix XenApp Server today and VMware’s VDI vision announcements this week include this ability.
- Offline or local VDI – the concept of either a local copy of a VM that synchronizes back to the cloud or a full client side hypervisor is being heavily discussed and developed today.
- Separation of User Personality from applications – the concept of encapsulating an application so that it does not need an anchor to one specific operating system is already possible by products like VMware’s ThinApp. Taking roaming user profiles and user data and encapsulating the user personality of a desktop is the next step. This modularity will enable all aspects of a virtual desktop to be streamed to a remote client no matter what the device or connection.
Mixed throughout this presentation Brian provided genuine and sincere analysis. He concluded with the comment “don’t buy VMware’s solution because of future awesomeness”. I am paraphrasing again, but his point was that a lot of the future vision is still just a vision. Brian closed by referring to a post he has written on brianmadden.com. His prediction is that VDI will overcome the challenges it faces today and exceed terminal services in seats deployed by the year 2010.