Introduction to desktop virtualization

I'm getting familiar with Xendestop - I've attended a workshop recently and read a bit. Desktop virtualization is less popular then server virtualization, but it's slowly getting more attention in large corporations, government organizations, universities etc. - everywhere you have dozens or hundreds of desktops sharing the same configuration.

How?

Desktop virtualization comes in many forms. You can use thin client or PC as an endpoint. Usually in addition to  standard protocols like RDP or VNC, they use a proprietary one with more features - for example, handling remote hardware (thin clients these days come with soundcards, cameras, DVD drives, USB ports), better network utilization. On a PC client, you can use a specialized software or a browser-based client - useful for one-time access from a remote machine. Some PC clients can also work offline

On the server end, you can run multiple desktop OSes on one server. This form, called VDI, is the most popular for obvious reasons - lower costs, better hardware utilization, less power, cooling and rack space. Another solution is to use one physical machine per client. It's useful when you need a specialized hardware on the client but still want to benefit from other advantages of desktop virtualization. You can also virtualize a single app - it'll run in it's own isolated environment, but from a user's perspective it'll look like it's running on his or her system. Xendesktop can combine all three forms.

Why?

Decoupling software and data from hardware is one advantage. If your terminal fails, replace it and continue working. Log on with your credentials to any box in the company and you get your own desktop.

But the real benefit is centralized administration. All desktops using the same operating system can be run from the single image. Ever had to install patch on 10 machines? How about 1000 and a full operating system upgrade? Plus, you don't have to experiment on a live system - prepare a new image, test it and then change the users' configuration: at the next login, they'll get a new system. Users can't do any damage to their OS, the machine image is read-only and user data is isolated from it.

Why not?

There are downsides, too. You need a reliable, redundant hardware and skilled operators, otherwise a single failure will make your whole IT infrastructure unusuable. The system is best suited for office employees. IT engineers will want to meddle with their setup, run different OSes, use strange hardware. People who work with graphics-intensive apps, eg. for video editing, would notice a degraded performance. Current systems handle low-quality video (eg. flash animations) quite well, but full resolution movies or games would quickly bring your network to its knees (actually, the system that can't run games and movies can be considered superior in a workplace).