In a computer system, to enable a second computer to take over control of copying of data within the computer system, from a first computer that normally controls copying of data.The second computer selects from a plurality of storage systems a storage system to be accessed in order to acquire sub system pair information, and acquires sub system pair information from the selected storage system. Based on the acquired sub system pair information, the second computer generates system pair information that includes copy pair information relating to a plurality of storage areas belonging to the plurality of storage systems. The second computer initially selects a storage system directly linked to the second computer, and subsequently sequentially selects a storage system based on the acquired sub system pair information.