Server virtualization is one of the hottest topics in IT today. Initially driven by the need to consolidate servers to achieve higher hardware utilization rates, boost operational efficiency, and reduce costs, enterprises have recently implemented virtualization to obtain on-demand access to additional compute resources. This enables enterprises to add processing and storage capacity "on-demand" as required, in order to respond to changing business conditions. Because virtualization allows them to move resources from more-congested to less-congested hosts as required, enterprises also benefit from improved server reliability, which increases application performance. And, consolidating servers through virtualization helps companies achieve "greener" data center operations that are increasingly mandated by corporate sustainability programs.