Patent ID: 8099547

Claim:
A load sharing method in a computer system including a storage subsystem, a host computer to be connected to the storage subsystem, a management computer to be connected to the storage subsystem, and a plurality of communication paths and, in the computer system, the host computer including a first interface to be connected to a network, a first processor to be connected to the first interface, and a first memory to be connected to the first processor, the management computer including a second interface to be connected to another network, a second processor to be connected to the second interface, and a second memory to be connected to the second processor, the storage subsystem including a controller that performs control over data reading and writing from/to a plurality of disk drives, the controller including a plurality of host interfaces to be connected to the host computer, a disk interface to be connected to the disk drives, a third processor to be connected to the plurality of host interfaces and the disk interface, and a third memory to be connected to the third processor, the storage subsystem configuring a disk drive group from the plurality of disk drives and creating a plurality of logical units from a storage area of the disk drive group, the host computer creating a logical storage area to be configured by a plurality of virtual logical units respectively corresponding to the plurality of logical units, the plurality of communications paths being respectively set between the host computer and the plurality of logical units configuring the logical storage area, each of the communication paths corresponding to one of the plurality of host interfaces, and the host computer accessing, through access to the virtual logical units, the plurality of logical units over the communications paths, the load sharing method comprising: monitoring, by the storage subsystem, a band of use of each of the plurality of host interfaces in the storage subsystem and a band of use of each of the plurality of logical units; detecting, based on a result of monitoring the band of use of each of the plurality of host interfaces, a first host interface having a largest band use value among the host interfaces and a second host interface having a smallest band use value among the host interfaces upon any imbalance occurring between the plurality of host interfaces; detecting, based on a result of monitoring the band of use of each of the plurality of logical units, a specific logical unit having a band use value that is closest to half of a difference between the band use value of the first host interface and the band use value of second host interface among each of the plurality of logical units for which the respective communication path corresponds to the first host interface; and changing, by the storage subsystem, the communications path between the specific logical unit and the host computer from corresponding to the first host interface to corresponding to the second host interface.