So what is virtualization? Wikipedia defines virtualization as:

“virtualization is the process of presenting a logical grouping or subset of computing resources so that they can be accessed in ways that give benefits over the original configuration. This new virtual view of the resources is not restricted by the implementation, geographic location or the physical configuration of underlying resources. Commonly virtualized resources include computing power and data storage.”

So what does that really mean, and why did it take so long for this technology to surface?

Virtualization has been around for a long time in many forms. Take the Apache web server for example. Apache can host multiple websites from 1 location. In the apache configuration file these are referred to as “Virtual Hosts”. This gives apache to present multiple web sites as if wach had it’s own server.

Server virtualization technologies work in a similar manner. Products like VMware take a single piece of physical hardware, and presents multiple “virtual machines”. To the operating system, these virtual machines look, feel, smell, and taste like physical hardware. When the operating system scans what it sees as a PCI bus, it’s going to find what it thinks is a real NIC, a real SCSI adapter, a real disk.

VMware can do this because the majority of servers do not utilize a server’s full resourses. In fact, the majority of systems are only 10% utilized. This means that 90% of that systems CPU, RAM, NIC bandwidth, and disk I/O are not being used. By taking those unused resources and sharing them between multiple virtual machines allows you to get 80 to 90% utilization from your hardware.

Higher utilization means more processing power for your dollar, ruble, peso, or whatever denomination you use.