  Data centers are the building blocks of IT business organizations providing
the capabilities of centralized repository for storage, management, networking
and dissemination of data. With the rapid increase in the capacity and size of
data centers, there is a continuous increase in the demand for energy
consumption. These data centers not only consume a tremendous amount of energy
but are riddled with IT inefficiencies. All data center are plagued with
thousands of servers as major components. These servers consume huge energy
without performing useful work. In an average server environment, 30% of the
servers are "dead" only consuming energy, without being properly utilized.
Their utilization ratio is only 5 to 10 percent. This paper focuses on the use
of an emerging technology called virtualization to achieve energy efficient
data centers by providing a solution called server consolidation. It increases
the utilization ratio up to 50% saving huge amount of energy. Server
consolidation helps in implementing green data centers to ensure that IT
infrastructure contributes as little as possible to the emission of green house
gases, and helps to regain power and cooling capacity, recapture resilience and
dramatically reducing energy costs and total cost of ownership.
