The present invention is one memory system storing the data for the computer to use, transmitting the data to other memory system and copying the data in other memory system while the computer maintains the integral copied data without providing the write time to the written data. The memory system provides the write time to the written data when the write time is provided or provides the record time to the written data when the write time is not provided. The other memory system stores the written data in the logical volume according to the write time.