Brian Madden: Terminal Services versus VDI
These are my notes summarizing Brian Madden’s one hour long Terminal Services versus VDI presentation at VMWorld Europe 2009. I will highly recommend that you should watch Brian’s video, he is insightful, lively and articulate, you’ll enjoy him while learning from it as I did.
Background
Both Terminal Services (TS) and Virtual Desktop Infrastructure (VDI) employ server-based computing (SBC) and offer the benefits that are inherent to SBC, namely
- Central management
- Central access control
- High performance
- Security
Historically, several applications have been found not to work with SBC due to limitations of remote display protocols, although the end-user often views it as an application compatibility issue. Typically applications that are multimedia, graphic-intensive, or write their state to proprietary folders on a local disk drive, or require multiple monitors, or a hardware security dongle, are known to break.
Should I use TS and VDI?
If you have to answer this question, you should first identify which applications are SBC compatible. Once you have identified them, then you should decide between TS and VDI.
TS advantages:
- Very high user density (By contrast, VMWare VDI supports only 6 to 8 users per core today)
- Proven solution/Mature technology (80 Million users/lot of user experiences on wiki’s and training material on the Web. By contrast, VDI is cutting edge, there is a learning curve coupled with a dearth of usage-based content)
- Automatic “thin” provisioning: All users share a common copy of OS/app code
VDI advantages:
- Live migration for load balancing, supporting mobile users
- VM’s can be rebooted without rebooting the host
- Suspend/resume of VM’s possible (TS disconnect continues to consume resources)
- Fault tolerance per user (since each user has their own VM)
- Competition amongst vendors (Citrix was a monopoly for TS, now VMWare, Microsoft, Citrix and several other vendors are investing in the future of VDI)
Brian showcased Atlantis Computing as an innovator that dynamically composes a bootable virtual disk (vhd or vmdk) for booting a VM.
VDI disadvantages:
- Disk space: 10GB per user in the data center (cost per GB in data center is 5X to 10X its cost on the desktop)
- Routine Op’s: How to run AV, backup, patch one master image
Brian’s predictions for 2010:
- Improving user density
- Remote Display Protocol improvements
- Thin provisioning/ Windows layering
- Offline VDI/Local hypervisors
- Local personality/Application management
Brian possesses journalistic flair; his posts are always insightful and thought-provoking. I have become a great fan of his blog.
