Patent ID: 8078814

Claim:
A storage system, comprising: a plurality of host computers; at least one storage subsystem; and a management computer, wherein each storage subsystem includes volumes storing data requested by the host computers to be written, the volumes including primary volumes from which data is copied, and secondary volumes to which data is copied, wherein the primary volumes and the secondary volumes form copy pairs, wherein the management computer is configured to: (A) obtain a plurality of copy pair definition information from each of the plurality of host computers, the plurality of copy pair definition information indicating associations between the primary volumes and the secondary volumes; (B) remove at least one duplicate copy pair definition information from the copy pair definition information obtained from the plurality of host computers by executing to: (B1) pick up a certain copy pair definition information from the plurality of copy pair definition information obtained from the plurality of host computers, register the certain copy pair definition information in an information obtaining definition table and delete the certain copy pair definition information from the plurality of copy pair definition information obtained from the plurality of host computers; (B2) remove a copy pair definition information which duplicates the certain copy pair definition information from the plurality of copy pair definition information obtained from the plurality of host computers; and (B3) repeat steps (B1) and (B2) until no copy pair definition information is left in the plurality of copy pair definition information obtained from the plurality of host computers; and (C) collect copy pair statuses of the copy pairs from the at least one storage subsystem via each of the host computers, based on the copy pair definition information registered in the information obtaining definition table, to avoid obtaining copy pair status of the same copy pair more than once.