January/February 2009

Demystifying Virtualization

 Computer virtualization is a concept that describes dividing computing resources into smaller or "virtual" parts. The computing resources can be hardware or software based. The earliest examples of virtualization can be found in partitioning mainframes in the 1960's where multi-programming shared resources and users didn't have to wait for peripherals. 

 Moore' Law is often used to explain why virtualization is so resourceful.  The informal definition of Moore's Law is that computing performance doubles every eighteen months. This means that today's computer has performance to spare and virtualization divides the machine into multiple machines without sacrificing speed.

Computer virtualization has many flavors and becomes quite technical. In this summary, we will give an overview of the most common type of virtualization in use - server virtualization. 

Server virtualization - There are basically two types of server virtualization.  The first is where different operating systems are run on the same hardware.  For instance, you could run a Microsoft Windows OS and a Linux OS on the same hardware. The different OS installations would run their own applications and even share data.   

The second type is running multiple copies of the same OS like Microsoft Server.  This allows you to run several less demanding application servers on the same hardware without stressing resources. This type of virtualization is only recommended for low-medium demand and is not recommended for high-performance applications. For instance, you could use Server Consolidation to run two or more Windows Servers that run specific applications on a single server.