Many of us have tried ways to run multiple operating systems on a single physical computer. Probably the most notable product in this area has been VMWare . Microsoft is catching on with its own Virtual PC offering and of course there is Parallels which came out of the Apple world.
One thing about virtualization that is not widely known is that it is an old principle (in computer time terms). It was actually used in the days when mainframes were the only game in town for high end computing needs.
One problem that was often encountered when running multiple operating systems on the same physical computer is that of performance. There was always a significant degradation which largely speaking ruled out any chance of using virtualization in a production server setting. I first noticed changes in this whilst with a client in Arizona back in 2005. They had built a very flexible lab-QA-Test environment using VMWare. This interested me because they were able to load-test code fairly aggressively and get reasonable performance even though it was running in a virtual environment, that got me thinking.
Recently, I attended a conference in San Antonio Texas and there was a presentation by a company called Xensource. Xensource seem to be taking virtualization to a new level and I think I am right in saying the company came out of an open-source initiative called “xen”. Xensource were recently acquired by Citrix and I think this in indicative of another trend centered around creating distributable complete environments with runnable applications. This is addressed to a certain extent by this section from the Xensource web site.
- Portability: The use of abstract devices within virtual machines, combined with the encapsulation of virtual data in file-backed or volume-backed virtual disks, makes it easy to move virtual machines from one physical system to another, for maintenance, more effective resource utilization, or simply for replicated provisioning.In many cases, running virtual machines can even be moved while they are online, with no interruption to service.
We will be doing more work here at Alagad around the whole topic of virtualization. The next steps will be to take one of our Windows 2003 lab servers and install Xensource on there and then follow that by attempting to install different operating systems and hopefully ColdFusion. I will be blogging about that in the near future as we move through each stage.
It seems to us that virtualized servers will play a large part in the continuing evolution of computing. I wonder how many servers sitting in data centers and dedicated to a specific task are under utilized ?