Virtualization is software technology that allows multiple operating systems to run simultaneously on a single physical computer. It is a way of maximizing physical resources to maximize the investment in hardware.Virtualization is the creation of a virtual (rather than actual) version of something, such as an operating system, a server, a storage device or network resources. The main benefit of virtualization is that it can cut a business' IT costs. For instance, a business with multiple servers could use server virtualization to eliminate Y number of those physical servers, freeing up space and cutting down on the energy, maintenance and security costs related to their physical IT plant.
 

Key Benefits of Server Virtualization are
 
1. Physical Servers dramatically get reduce by implementing Virtualization.
 
2. Data Center space get reduce due to less number of Physical Servers.
 
3. Leads your company towards Green IT by reducing power used by Physical Servers.

4. By having each application within its own "virtual server" you can prevent one application from impacting another application when upgrades or changes are made.

5. You can develop a standard virtual server build that can be easily duplicated which will speed up server deployment.

6. You can deploy multiple operating system technologies on a single hardware platform.
 
7. Increase efficiency for development and test environments.
 
8. Improve availability and business continuity
 
9. Fewer servers also reduce physical server maintenance for administrators.
 
10 Dynamic Load Balancing and Disaster Recovery
 
Major Players in the Server Virtualization Arena today are
 
VMware
Citrix
Sunmicrosystems
Microsoft
Oracle
Parallels
Virtual Iron