Remote copy system

A remote copy system comprising:

• a first storage system connected to a first upper level computing system to transmit or receive data to or from the first upper level computing system;
• a second storage system connected to the first storage system to receive data from the first storage system;
• and
• a third storage system connected to the second storage system to receive data from the second storage system and connected to a second upper level computing system to transmit or receive data to or from the second upper level computing system,
• wherein the first storage system has a first storage area on which the data transmitted from the first upper level computing system is written,
• wherein the second storage system has a logical address on which the data transmitted from the first storage system is written and a second storage area on which data to be written on the logical address and update information on the data are written,
• wherein the third storage system has a third storage area on which the data read from the second storage area and update information on the data are written and a fourth storage area where the first storage area is copied, and
• wherein, after a predetermined time, the data written on the second storage area and the update information are read from the third storage system and are then written to the third storage area.