The invention further includes a control unit, when there is no access from {TAIL ~ the host unit} to the logical unit for a predetermined time, for determining {HEAD ~ the disk units} corresponding to the logical unit based on information recorded in the management information recording device and performing power saving of power supply for the disk units 
The invention further includes a control unit , when there is no access from { TAIL ~ the host unit } to the logical unit for a predetermined time , for determining { HEAD ~ the disk units } corresponding to the logical unit based on information recorded in the management information recording device and performing power saving of power supply for the disk units
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH