When choosing among Kaviza, NComputing, and Pano Logic, the question becomes one of virtual machines versus a shared operating system environment for the end-user desktops. With Kaviza and Pano Logic, you can create different virtual machine images for different user profiles. With NComputing, all users run the same OS and applications as the host. In return for the generic user environment, both hardware and administrative requirements are lower.
Like a lot of IT hot-button topics, some admins feel strongly about one flavor of virtualisation versus another. During my tests, I had no problems with any of the VDI solutions. While I only scaled up to 10 concurrent users, all three performed well and none gave me any indication that I was in jeopardy of running out of resources.
Personalising virtual desktops
One of VDI's more interesting features is on-the-fly creation of clean virtual machines from standard images as users log on. By deploying nonpersistent desktop VMs, there is no chance of permanent damage from viruses, malware, or user error. To bring each user's personal settings to these dynamic desktop VMs (or to each user session, in the case of NComputing), the three solutions all take advantage of Active Directory roaming profiles.
Roaming profiles are one of the oldest ways to provide user personalisation on Windows-based networks. Through Active Directory group policy, a user's personalisation information is collected from the local profile and stored on a server somewhere in the domain. This stored profile includes the My Documents folder, Outlook email settings, printer assignments, desktop icons, and other settings that make the desktop environment unique to the user.
The roaming profile is part of the Windows user identity and independent of the underlying system. That means a roaming profile will provide the personal user settings to any Windows device in the domain: a physical desktop, virtual desktop, or Terminal Services user session. The profile is applied during the logon process, and any changes made during the session are saved on logout. Roaming profiles are not fancy, but they are very effective at giving the end-user the perception of a persistent desktop when in fact the virtual desktop is newly created upon each logon.
Making the virtual desktop connection
The connection broker is another important component, especially when it comes to handling a VDI infrastructure with dozens of users. With respect to VDI, a connection broker is a service that handles incoming user requests and automatically directs them to an available host server.
Kaviza does a good job of handling user access to desktop VMs and load balancing among host servers as part of its management platform. NComputing doesn't really have the concept of connection brokering because each user that connects to a vSpace host will run a session of the same operating system as the host itself. Users can pick and choose among vSpace hosts, but it is not an automatic process. Pano Express, like Kaviza, does provide connection brokering. The Pano Express solution can work with third-party connection brokers, too, to provide load balancing.
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