Which form of app virtualization is best: streaming or localized?

Virtualization technologies have created opportunities and use cases for many aspects of the data center including servers, storage, networks and even applications. While these technologies are not new, they are becoming more widely accepted and in turn, are raising a variety questions.

One common question is, "Which type of application virtualization should I apply to my environment?"

The answer: "It depends."

Application virtualization is where a program -- like Microsoft Word or Firefox -- is separated from the local desktop operating system. The two forms of this are streaming mode and localized mode.

• Streaming mode is when the application is being hosted from a centralized server (such as Citrix XenApp or Microsoft App-V) or a file share (like VMware ThinApp). This is currently the most popular method of application virtualization because Citrix has been doing it for years through its presentation server technology.

• Localized mode is when the application has been captured or packaged into a single file (using VMware ThinApp) or a cached copy (with Citrix XenApp). Both of these versions have different functionality that can suit certain use cases better.

When deciding which mode to use, ask yourself the following questions:

1. Will the end user always have a network connection?

   • If yes then streaming mode is still OK, but localized is also OK.

     The next question would be, "Do you want to build back-end servers to host the applications, whether virtual or physical, or do you want to allow the application to utilize the local desktop resources such as CPU or memory?"

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     1. If the answer is to build servers, then streaming is now the preferred method.

     2. If the answer is to use local resources, then localized mode is the better method.

   • If no, then streaming is not recommended, and localized will be the version needed for the use case.

2. Do you want to install and control the application via an agent on the local desktop?

   • If yes, then look toward a Citrix- or Microsoft-style deployment.

   • If no, then look toward a VMware ThinApp-style deployment.

When making these decisions, keep in mind that there are many more companies than what I have listed here, but these three give a good representation of the top tier of application virtualization providers. There is no stock answer for what is better for you. The decision has to be made through in-depth discovery, question and understanding of the use case.

ABOUT THE AUTHOR:   
Brad Maltz is CTO of International Computerware, a national consulting firm focused on virtualization and storage technologies. He holds certifications from VMware and EMC for many technologies. Maltz can be reached at [email protected] for any questions, comments or suggestions.