Patent ID: 7836251

Claim:
A storage controller which is coupled to a host device and a plurality of storage devices, the storage controller comprising: a plurality of RAID groups, each of which is configured from some of the plurality of storage devices; logical storage devices which can be set on each of the RAID groups; an access information collection portion which collects access information about the RAID groups and the logical storage devices; a power supply mode setting portion which sets a power supply mode for supplying power for each of the RAID groups; a power control portion which controls supply of power to each of the storage devices configuring each of the RAID groups, on basis of the set power supply mode; and a relocation execution portion which moves a logical storage device, which is judged as a target of relocation from among the logical storage devices, from a source RAID group to a destination RAID group, wherein (1) the power supply mode setting power portion determines an access frequency to the RAID groups on the basis of the access information about the RAID groups, (1-1) sets a long time energization mode in which a power supply time period is relatively long for first RAID groups of the RAID groups in which the determined access frequency is relatively high, and (1-2) sets a short time energization mode in which a power supply time period is relatively short for second RAID groups of the RAID groups in which the determined access frequency is relatively low; (2) the relocation execution portion determines an access frequency to the logical storage devices on the basis of the access information about the logical storage devices, (2-1) selects one of the first RAID groups as the determination RAID group of the logical storage device in which the determined access frequency is relatively high; and (2-2) selects one of the second RAID groups as the determination RAID groups of the logical storage device in which the determined access frequency is relatively low.