VMware Distributed Power Management Concepts and Use
Consolidation of physical servers into virtual machines that share host physical resources can result in significant reductions in the costs associated with hardware maintenance and power consumption. VMware Distributed Power Management (VMware DPM) provides additional power savings beyond this initial benefit by dynamically consolidating workloads even further during periods of low resource utilization. Virtual machines are migrated onto fewer hosts and the un-needed ESX hosts are powered off. When workload demands increase, ESX hosts are powered back on and virtual machines are redistributed to them. VMware DPM is an optional feature of VMware Distributed Resource Scheduler (VMware DRS).