Patent ID: 8020016

Claim:
An electric power control method of controlling electric power consumption of a computer system, the method being carried out on a computer system having at least one server and at least one data processing apparatus, wherein the computer system further having at least one management server for managing the at least one data processing apparatus, wherein the electric power control method comprises the steps of: a relationship management step of managing a use relationship between the at least one server and the at least one data processing apparatus included in the computer system; a state monitoring step of monitoring a change in a state of the at least one server; an obtaining step of obtaining the electric power consumption of the computer system; a relationship search step of searching for a related data processing apparatus in the use relationship with the at least one server; a state determination step of obtaining a state of at least one related server in the use relationship with the related data processing apparatus, and determining whether the electric power consumption of the related data processing apparatus is to be changed or not based on the state of the at least one related server and the obtained electric power consumption of the computer system; and an electric power consumption control step of changing the electric power consumption of the related data processing apparatus, wherein: the at least one data processing apparatus is an external storage system which comprises physical disks for storing data accessed by the at least one server, and on which a RAID group is logically created by a set of the physical disks; the electric power consumption control module changes electric power consumption of the physical disks included in each of the RAID group; the relationship management step includes a step of obtaining a use relationship between the at least one server and the RAID group accessed by the at least one server from the at least one server and the external storage system; the external storage system can select more than two levels of electric power consumption states of the RAID group which correspond to different performance levels; the at least one management server holds setting policies of states of the electric power consumption of the RAID group which is used by the at least one server according to the state change of the at least one server; and the electric power consumption control step includes a step of determining one of the set levels of the electric power consumption state of the RAID group based on the setting policies.