Patent ID: 7689787

Claim:
A control device of a computer system in which a plurality of host computers are capable of sharing a same host interface of a storage system, wherein the storage system comprises: a plurality of host interfaces capable of being shared by the plurality of host computers, a plurality of virtual logical volumes (VVOLs) respectively provided to the plurality of host computers, and a plurality of actual logical volumes (VOLs) mapped to any of the plurality of VVOLs, wherein a plurality of logical paths that pass through any of the plurality of host interfaces span between the plurality of host computers and the plurality of VVOLs, and the host computers access, via paths spanning to themselves, the VVOLs connected to these paths, thereby achieving access to a VOL mapped to a VVOL and wherein the control device comprises: a VOL status monitoring portion that monitors a VOL status of each VOL mapped to the VVOLs and determines whether or not the VOL status of each VOL mapped to the VVOLs is changed; and a path number control portion that updates a number of paths connecting to a target VVOL, which is a VVOL in which a VOL status has changed, wherein the VOL status monitoring portion calculates a VOL evaluation value for each of the VOL based on a VOL attribute of the VOL, wherein the VOL status is the VOL evaluation value, wherein the target VVOL is a VVOL whose VOL evaluation value calculated of a VOL being mapped is different from a previously calculated VOL evaluation value, wherein the control device further comprises a storage area in which attribute management information is stored, wherein the attribute management information is information representing attribute evaluation values that have been set respectively for a plurality of VOL evaluation values corresponding to a plurality of types of VOL attributes, and wherein the VOL status monitoring portion specifies attribute evaluation values corresponding to VOL evaluation values of various VOL attributes of the VOL for each VOL and calculates VOL evaluation values of the VOL based on the specified plurality of attribute evaluation values.