provided is a copy pair monitoring method which is for a storage system having at least one host computer , at least one storage subsystem , and a management computer , the storage subsystem including volumes storing data requested by the host computer to be written , the management computer being accessible to the host computer and the storage subsystem . the copy pair monitoring method is characterized by including the steps of : obtaining every piece of copy pair definition information that is stored in the host computer ; removing duplicate copy pair definition information from the whole copy pair definition information obtained ; and collecting the copy pair status based on the obtained copy pair definition information from which duplicate copy pair definition information has been removed .