Matrix Revisited

From the Sept. 2007 Issue

Most of you should remember the movie with Keanu Reeves where he played Thomas A. Anderson (aka Neo) and worked with his futuristic cohorts in virtual reality to combat the evil forces led by Agents Brown, Smith and Jones. The film was pure fiction, but as with many fictional ideas there is some reality. I’m writing this month about the world of virtual servers and desktops. Virtualization can be defined as a technique for hiding the physical characteristics of computing resources from the way in which other systems, applications or end users interact with those resources. In other words, applications, other systems and end users don’t know (or care for that matter) that the server to which they’re connecting isn’t a physical box filled with a motherboard, processor, memory and network cards, but rather a piece of software that is using a small portion of those physical resources.

Virtualization is fast becoming mainstream, with businesses attracted by the significant cost savings associated with running eight to 10 virtual servers on a single hardware host system. Previously, hardware manufacturers hadn’t included support for virtualization into their various hardware platforms, perhaps for obvious reasons since virtualization tends to eliminate the need for more hardware. However, current hardware components have specific support for virtualization. Case in point: Intel Virtualization Technology ( Intel VT). This technology is a set of hardware enhancements to Intel server and client platforms that is intended to improve traditional software-based virtualization solutions. Software virtualization solutions enhanced by Intel VT can improve the performance and robustness of software-only virtual machine solutions. Not to be outdone, AMD has also introduced hardware support for virtualization called AMD Virtualization.

These new generation motherboards and processors, along with virtualization software, more efficiently use resources provided to the host system. Most servers chug along at 10 to 20 percent of capacity. So instead of seven machines running at 10 percent utilization, you run one machine at 70 percent utilization. Beyond the savings in hardware, you’ll reap savings in power, space and cooling since there are fewer machines running, and there are personnel savings as fewer administrators are needed for hardware maintenance. These software-only virtual machines are encapsulated into files, making it possible to rapidly save, copy and provision a virtual machine. Full systems (fully configured applications, operating systems, BIOS and virtual hardware) can be moved, within seconds, from one physical host server to another for zero-downtime maintenance and continuous workload consolidation.

Ever have a server go down? This creates significant anxiety while high hourly rate professionals sit around waiting for their services to be restored. With virtual machines, the encapsulated file can be quickly moved to a functioning host and restarted. If the virtual machine image itself has stopped functioning perhaps because of a software update or change, the previous copy of that image allows for a ‘roll-back’ option to a previous time when the server was functioning. Obviously, virtual machines facilitate testing also. For example, Windows Vista was recently released, and I was curious as to how many of the tax and accounting applications would behave well when installed on Vista. Installing these on a ‘virtual Vista’ machine allowed for an answer to my question, and, if the machine became non-functional as a result of my testing, I simply deleted that virtual machine file and fired up the original one. Since I wanted to move to Vista on my desktop machine (and many of these applications didn’t run on the new operating system), I have a virtual machine running XP on my Vista host system. This worked well for me as I fired up the XP virtual machine every time I needed to use one of those applications that didn’t run on Vista and quickly switched back to my Vista host for other tasks that did.