Virtualization 101

Virtualization fundamentally changed computing in a way that was unforeseen as recently as five years ago. Every area of the economy that utilizes computing has been impacted, from financial, telecom, and healthcare sectors to retail, manufacturing, media, and government. In addition to improving key data center processes, such as Business Continuity (BC) and High Availability (HA), virtualization provides companies with flexibility, cost savings, and disaster recovery options critical to their success.

What is Virtualization?

Simply put, server virtualization consists of running multiple operating systems and applications on the same server at the same time. The current process of partitioning one physical server into several operating systems, or virtual machines (VMs), lets you simultaneously deploy, operate, and manage these multiple operating system instances on that single physical server.

The concept of virtualization originated back in the era of mainframes. Today’s advances, especially the introduction of Intel x86 architecture and inexpensive PCs, finally made virtualization technology possible. This innovation enabled companies of all sizes to flexibly accommodate a multitude of users, extend the life of their datacenters, and save on hardware purchases and utility costs, in addition to streamlining server administration.

Moreover, virtualization substantially leveled the economic playing field, enabling small to medium businesses (SMBs) to compete and reach parity with much larger enterprises, something that was impossible a few years ago.

For SMBs, virtualization increases application availability and can dramatically shorten disaster recovery time to significantly improve business continuity preparedness.

For enterprises, virtualization offers levels of efficiency in security, management, automation, and VM deployment as well as the ability to provide increased resources to more users.

Advantages of Virtualization

There are a number of key areas in which virtualization offers companies important benefits:

Energy efficiency

By stacking multiple applications on a single server and sharing resources among them, virtualization optimizes server utilization and cuts waste. Lessening the physical size of datacenters also results in energy efficiency, decreased hardware costs, and maintenance savings.

Improved server utilization

Removing the physical relationship between an OS and its native hardware with virtualization greatly expands server capacity and avoids under-utilization where, in some instances, single servers use less than 30 percent of their processing power.

Architecture control

Virtualization enables companies of all sizes to simplify datacenter architecture. Virtualization not only provides built-in redundancy by spreading the computing power across multiple inexpensive machines, it also ensures a server resource pool.


The role of automation means that VMs can be copied, administered, and restored easily. Single-console management of VMs adds another layer of efficiency and increases response times during emergencies. The ability to shift VMs or other resources to a different server is another key feature. Administrators can conduct maintenance without interrupting service, disabling a system, or having to work off-hours.

Types of Virtualization

A common aspect of server virtualization renders each operating system instance independent of the other OSs on the same server. In this way, VMs are typically full implementations of a standard OS, such as Windows 7, running side by side with many other instances, for example, versions of Windows Vista or RedHat Enterprise Linux. Each OS then runs its own applications that are accessible to an almost unlimited number of users.

In the case of desktop virtualization, the client OS runs on a server in the datacenter and is delivered virtually to a user. It offers greater workplace efficiency, lower costs, and increased scalability for IT managers. Virtualized desktop users have the ease of mobility — they can access their desktop from anywhere by logging in as a unique user.

Essentially, there are four types of desktop virtualization:

  • Thick client: This is a standard desktop supplied with a virtual desktop image delivered from the datacenter.
  • Thin client: This employs a stripped-down OS and supports the user interface functionality (video, audio, printer, mouse, keyboard).
  • Net client: This can be a mobile device, such as an iPhone running a specific OS.
  • Zero client: All of the operating system runs on a server in the datacenter and is sent out to the client, nothing at desktop.

User virtualization provides the ability to maintain a fully personalized virtual desktop when not on the company network. For example, users can log into a workplace desktop from anywhere with all the settings and applications in place using a smart phone, tablet, or laptop.

For IT, user virtualization provides the ability to manage desktop components independently and apply them to a workspace as needed without scripting or group policies. IT administrators can perform:

  • settings management
  • workplace configuration
  • application lock-downs
  • streamlined management

In terms of application virtualization, formerly referred to as ‘thin client,’ applications are not installed locally on a workstation. Personal information and unique application characteristics are all stored on, managed, and delivered via a remote service. The local device provides the CPU and RAM required to run the software. Thus, the virtual applications run locally, but the management and application logic run remotely.

Next week will wrap this series up with a look at the top Virtualization players.

Excerpted from Global Knowledge: Virtualization 101

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