Storage system, data protection method and management computer, including arrangement for data replication between storage devices

A storage system comprising:

• a first storage device including at least one or more first logical units;
• a second storage device including at least one or more second logical units;
• and
• a management computer that conducts configuration related to a copy pair in which data is replicated from a first volume in the at least one or more first logical units configured to be a primary system to a second volume in the at least one or more second logical units configured to be a secondary system,
• wherein the first storage device has a first management unit that manages first information including a first number of total read/write commands from a first host to the first volume,
• the second storage device has a second management unit that manages second information including a second number of total read/write commands from a second host to the second volume, and
• the storage system further comprising:
• a determining unit that determines whether data replication from the first volume to the second volume or data replication from the second volume to the first volume is replication from the primary system to the secondary system based on a comparison between the first number and the second number, when the management computer makes an instruction to configure data replication from the first volume to the second volume,
• a display unit that displays a determined result of the determining unit on the management computer if the first number is less than the second number, and
• a data replication unit that replicates the data from the first volume to the second volume if the first number is greater than the second number.