This selective approach can also help balance performance, notes CSU’s Washburn. Were Washburn to deliver everything as streams, it would take client PCs five minutes or more to boot up -- a nonstarter. So he installs core applications on the PCs the old-fashioned way, using Altiris’ remote deployment tools, and provisions less frequently used programs via application streaming.
Yet another variation is to combine application streaming with terminal services. At Alamance Regional Medical Center in Burlington, N.C., senior network administrator Andy Gerringer uses both Citrix and SoftGrid to provision desktops. Citrix is used in the usual manner to deliver server-based applications as individual sessions. But Alamance also uses Citrix to provide access to a SoftGrid desktop environment for terminal users. Essentially, the Citrix session runs the SoftGrid virtual machine. “SoftGrid and Citrix complement each other very well,” Gerringer says.
Conflict resolution for applications
Application streaming comes with a significant side benefit: eliminating application conflicts. The application streaming tools from AppStream, Altiris, and Microsoft separate application-specific support files such as DLLs and libraries from the underlying operating system. Altiris separates just the support files, keeping the applications with the operating system, whereas AppStream and Microsoft keep each app and its support files together in one virtual layer or package.
These programs manage the communication among the layers and the underlying operating environment, so both Windows and its users think they are working on a single environment. By separating each application into its own virtual layer (or package, as some call it), these products prevent software conflicts common with homegrown software and some commercial applications. And user-installed applications can’t conflict with IT-provisioned applications in the virtual layers, says Microsoft’s Grescher.
For example, before adopting SoftGrid, recalls Alamance’s Gerringer, the medical center had to maintain separate servers for ill-behaved apps, forcing users to switch among multiple systems from their terminals. “By summer 2005, the problem got too big to manage anymore the old way,” Gerringer says.
The problem? Different versions of Java used by various specialty health care apps prevented simultaneous usage, as did the embedding of different versions of the Crystal Reports reporting tool in other applications. (If Crystal Reports 4 is running, Crystal 5 cannot run, for example.)
Now that Alamance uses SoftGrid, users get a unified desktop environment, with the ill-behaved apps corralled so they can no longer cause trouble.
The new reality of virtualization
Desktop and application streaming require IT to think differently about tasks that they’ve done for years, notes Neal of Duncan Regional Hospital. “It takes a little more thought in the rollout,” he says. For example, his support staff now has to keep an eye on the blades that serve the desktop environments, because a broken fan can cause them to overheat, knocking out multiple users in one blow. His staff also must monitor disk usage for each blade, because 80GB is shared among three users.