What Is Server Virtualization and Microsoft Hyper-V?

Hyper-V is a long-awaited technology that has been anticipated to help Microsoft leap past rival virtual server technologies such as VMware and XenServer. Although Microsoft has had a virtual server technology for a few years, the features and capabilities have always lagged behind its competitors. Windows Server 2008 was written to provide enhanced virtualization technologies through a rewrite of the Windows kernel itself to support virtual server capabilities equal to, if not better than, other options
on the market. The Hyper-V server role in Windows Server 2008 and provides best practices that organizations can follow to leverage the capabilities of server virtualization to lower costs and improve the manageability of an organization’s network server environment.

Server virtualization is the ability for a single system to host multiple guest operating system sessions, effectively taking advantage of the processing capabilities of very powerful servers. Most servers in data centers run under 5% to 10% processor utilization, meaning that excess capacity on the servers goes unused. By combining the workloads of multiple servers onto a single system, an organization can better utilize the processing power available in its networking environment.

Hyper-V enables an organization to consolidate several physical server systems into a single host server while still providing isolation between virtual guest session application operations. With an interest to decrease costs in managing their information technology (IT) infrastructure, organizations are virtualizing servers. Bringing multiple physical servers into a single host server decreases the cost of purchasing and maintaining multiple physical server systems, decreases the cost of electricity and air-cooling systems to maintain the physical servers, and enables an organization to go “green” (by decreasing the use of natural resources in the operation of physical server systems).

Source of Information : Sams - Windows Server 2008 Hyper-V Unleashed