(Click on the title above to access the paper.)
A Webtorials Brief
Jim Metzler, Cofounder, Webtorials Editorial/Analyst Division
Abstract:
Desktop virtualization is a classic good news/bad news situation. The good news is that because it simplifies some management tasks, improves security, and increases the reliability of desktop services, desktop virtualization helps IT organizations achieve some of the goals of application delivery. The bad news is that if IT organizations don’t implement the appropriate optimization, control and management functionality, the deployment of virtualized desktops will result in unacceptable application performance.
Relative to optimization functionality, techniques such as TCP optimization as well as compression and caching can provide some performance improvement, primarily for applications that are not part of the VDI traffic stream. The real performance gains come from deploying QoS and bandwidth management in order to ensure that screens refresh in a reasonable amount of time as well as to ensure the acceptable performance of applications video.
Control functionality is needed in order to automatically protect keyboard strokes and screen refreshes from other traffic types and to also ensure sufficient capacity to effectively support audio and video traffic. Because of the complications created by both CGP and session sharing mode, it is not possible to implement this type of control by utilizing the ICA priority packet tag or by prioritizing flows based on the published application. This leaves prioritizing flows automatically according to their behavior as the most viable option.
The lack of management visibility is a barrier to application delivery independent of the IT infrastructure. However, a virtualized IT infrastructure is more complex than in a non-virtualized environment. This results in more sources of delay that can lead to unacceptable application performance. To compensate for this, IT organizations must implement solutions that give them the visibility to understand the user’s experience in real time. This type of visibility is necessary in order for IT organizations to focus on the company’s key applications and not just on the technology domains that support those applications.
Monday, June 15, 2009
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Jim, this paper opens up some of the challenges of the virtualized environment, but doesn't necessarily provide any deeper guidance. Will those be discussed in other papers?
ReplyDeleteAlso, most network-based solutions don't have intra-queue prioritization anymore. They reply upon inter-queue prioritization - which won't really help an IT shop out if they have intra-queue congestion. Would you recommend that the VDI environment stop publishing app suites as a single instance, but go back to per-app instances in such environments? Would staying in a per-desktop published environment mandate the use of deep-packet inspection?
You are right - this brief paper was just a high level beginning of the discussion around the impact of virtualization on application delivery. There will be additional papers, but the topics and timing are TBD.
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