What is Virtualization?

When people talk about virtualization, they’re usually referring to server virtualization, which means partitioning one physical server into several virtual servers, or machines. Each virtual machine can interact independently with other devices, applications, data and users as though it were a separate physical resource.

Different virtual machines can run different operating systems and multiple applications while sharing the resources of a single physical computer. And, because each virtual machine is isolated from other virtualized machines, if one crashes, it doesn’t affect the others.

Hypervisor software is the secret sauce that makes virtualization possible. This software, also known as a virtualization manager, sits between the hardware and the operating system, and decouples the operating system and applications from the hardware. The hypervisor assigns the amount of access that the operating systems and applications have with the processor and other hardware resources, such as memory and disk input/output.

In addition to using virtualization technology to partition one machine into several virtual machines, you can also use virtualization solutions to combine multiple physical resources into a single virtual resource. A good example of this is storage virtualization, where multiple network storage resources are pooled into what appears as a single storage device for easier and more efficient management of these resources. Other types of virtualization you may hear about include:

Network virtualization splits available bandwidth in a network into independent channels that can be assigned to specific servers or devices.
Application virtualization separates applications from the hardware and the operating system, putting them in a container that can be relocated without disrupting other systems.
Desktop virtualization enables a centralized server to deliver and manage individualized desktops remotely. This gives users a full client experience, but lets IT staff provision, manage, upgrade and patch them virtually, instead of physically.
Virtualization was first introduced in the 1960s by IBM to boost utilization of large, expensive mainframe systems by partitioning them into logical, separate virtual machines that could run multiple applications and processes at the same time. In the 1980s and 1990s, this centrally shared mainframe model gave way to a distributed, client-server computing model, in which many low-cost x86 servers and desktops independently run specific applications.

While virtualization faded from the limelight for a while, it is now one of the hottest trends in the industry again, as organizations aim to increase the utilization, flexibility and cost-effectiveness in a distributed computing environment. VMWare, Citrix, Microsoft, IBM, RedHat and many other vendors offer virtualization solutions.

Why Should You Care?

Virtualization can help you shift your IT focus from managing boxes to improving the services you provide to the organization. If you are managing multiple servers and desktops, virtualization can help you to:

Save money. Companies often run just one application per server because they don’t want to risk the possibility that one application will crash and bring down another on the same machine. Estimates indicate that most x86 servers are running at an average of only 10 to 15 percent of total capacity. With virtualization, you can turn a single purpose server into a multi-tasking one, and turn multiple servers into a computing pool that can adapt more flexibly to changing workloads.
Save energy. Businesses spend a lot of money powering unused server capacity. Virtualization reduces the number of physical servers, reducing the energy required to power and cool them.
Save time. With fewer servers, you can spend less time on the manual tasks required for server maintenance. On the flip side, pooling many storage devices into a single virtual storage device, you can perform tasks such as backup, archiving and recovery more easily and more quickly. It’s also much faster to deploy a virtual machine than it is to deploy a new physical server.
Reduce desktop management headaches. Managing, securing and upgrading desktops and notebooks can be a hassle. Desktop virtualization solutions let you manage user desktops centrally, making it easier to keep desktops updated and secure.