Patent ID: 8700932

Claim:
A method for on-demand power reduction within a storage subsystem of a data site having multiple storage devices, including at least one physical storage device and at least one virtual storage device, organized in a hierarchy, the method comprising: monitoring and reporting power consumption of the storage devices; monitoring and reporting data access performance on each of the storage devices, including storing policies of the storage devices; responsive to a request to limit power, using real-time heuristics to receive the reporting and to lower power usage of at least one storage device in the subsystem by at least a required amount while maintaining performance responsive to the stored policies, comprising: a first heuristic for selecting one of the devices in one of a selection of tiers in the hierarchy and lowering a power consumption setting of the selected device based upon a priority setting wherein the priority setting includes importance of operability of the selected device; and a second heuristic for measuring power consumption feedback after lowering the power consumption setting of the selected device based upon the priority setting, and adjusting selection of the devices according to the measured feedback, wherein availability of a device for power consumption setting adjustment is evaluated in the selected tier prior to selection of a device from a different tier.