Patent ID: 8112562

Claim:
In a system in which a plurality of paths extend between a plurality of ports possessed by a storage system and one or more external devices, the plurality of paths including a path which is being used as an I/O path and one or more paths which are being used as alternate paths, and with the path which is being used as an I/O path being a path which is used when the external device issues an I/O command, and the path which is used as an alternate path being capable of being used as an I/O path: a path changeover support device, comprising: a storage resource which stores port management information including information related to a status for each of a plurality of ports possessed by the storage system; a status detection unit which detects that a fault is occurring in an I/O path which is using a first port; a port selection unit which extracts a subject external device which are using the first port in the I/O path, selects a “normal” port from one or more ports related to one or more paths which are being connected to the subject external device; and a port notification unit which notifies the subject external device of information of the selected “normal” port, wherein the “normal” port is selected in order for the number of the external devices for all of the ports, except the first port, used in the I/O paths to become as equal as possible, wherein, if it has been detected by the status detection unit that recovery has been performed from a path fault, the port selection unit performs (1-1) and (1-2) below in relation to a subject external device which is using the path which has been recovered from the path fault: (1-1) on the basis of the port management information, deciding whether or not the number of I/O paths related to the current I/O port, which is the port related to the path which is being used as the current I/O path, is greater than the sum of 1 and the number of I/O paths related to the “maintenance completed” port, which is the port related to the path which has been recovered from the path fault; and (1-2) updating the port management information, if the result of the decision is affirmative.