Patent attributes
Systems and methods are directed to migrating virtual machine instances between equipment racks of, for example, a data center such that one or more of the equipment racks can be emptied of all active virtual machine instances. Power then can be reduced or completely shut off the racks emptied of their active virtual machine instances. Cooling for such racks also can be reduced. Energy and costs to operate and cool the racks thus are saved. Such techniques are particular beneficial during periods of reduced network activity (e.g., at night and on weekends). Also, all virtual machine instances running in a particular room of a data center can be migrated to server computers running elsewhere to thereby permit utilities (e.g., power, cooling) to the room to be reduced or shut down completely.