Virtualization technology is now becoming an important advancement in IT especially for business organizations and has become a top to bottom overhaul of the computing industry. It combines or divides the computing resources of a server based environment to provide different operating environments using different methodologies and techniques like hardware and software partitioning or aggregation, partial or complete machine simulation, emulation and time sharing.

Virtualization is a technique for abstracting (or hiding) the physical characteristics of computing resources from the way in which other systems, applications or end users interact with those resources. It is very important for an organization to know in advance the total content of its infrastructure before implementing virtualization. This is the most important step in any virtualization project.

Virtualization can be applied to operating systems, desktops, applications, storage and networks, depending on the end user business requirements. Virtualization technology is provided by many vendors including VMware, Cisco, Citrix, EMC, Hewlett-Packard, IBM, Microsoft, NetApp, Novell, Oracle, Quest, Sun, Symantec and Virtual Iron. Server virtualization has become popular in data centers since it provides an easy mechanism to cleanly partition physical resources, allowing multiple applications to run in isolation on a single server. It categorizes volume servers into different resource pools depending on the workloads they perform, and then server consolidation is applied. This technique decouples softwares from hardware and splits multi processor servers into more independent virtual hosts for better utilization of the hardware resources, allowing services to be distributed one per processor. In server consolidation, many small physical servers are replaced by one large physical server to increase the utilization of expensive hardware resources, reducing the consumption of energy and emission of \(CO_2\).

To properly implement virtualization, consider five key steps that need to be followed at different stages in a structural way to achieve the efficiency required in the data center:

1. Inventory process.
2. Type and nature of virtualization.
3. Hardware maximization.
4. Architecture.
5. Manage virtualization.

The reasons to consolidate and virtualize IT infrastructure that is, server are wide-ranging. Mostly, IT managers focus on just the cost of the physical IT infrastructure, but there are many additional benefits that can be derived from server consolidation like:

1. Achieving sustainable businesses.
2. Simplified management.
3. Improved data protection.
4. Improved resource utilization.
5. Easier revision control and flexibility.
6. Easier data protection and security.
7. Reduced server and software costs.
8. Proper utilization of servers.
9. Proper energy utilization.
10. Reduction in consumption of energy.
11. Reduction in emission of green house gases.
12. Reduction in global warming effects.

Servers are the major consumers of energy and they need to be consolidated using virtualization. This process comprises of the following sub phases:

1. Categorize server resources.
2. Select vendor (VMware, Citrix, Microsoft etc).
3. Apply server consolidation.