Patent ID: 8074036

Claim:
A data processing system comprising: a first storage system that is connected to a host device and sends and receives data to and from the host device; a second storage system that is connected to the first storage system and receives data from the first storage system; and a third storage system that is connected to the first storage system and the second storage system and receives data from the first storage system, wherein the first storage system includes a first storage area that stores data sent from the host device, and a second storage area that stores the data to be written in the first storage area and update information relating to the data to be written in the first storage area, the second storage system includes a third storage area that stores data sent from the first storage system, and a fourth storage area that stores the data to be written in the third storage area and update information relating to the data to be written in the third storage area, and the third storage system includes a fifth storage area that stores data read from the second storage area and update information relating to the data read from the second storage area, and a sixth storage area that stores data that is generated based on the data written in the fifth storage area and the update information relating to the data written in the fifth storage area, and wherein the first storage system, the second storage system and the third storage system are arranged to be changeable between a first status and a second status in response to a predetermined condition at the first storage system, (1) the first status including: a) a first copy procedure, according to a first copy pair being formed between the first storage area and the third storage area, in which the data to be written in the first storage area is copied to the second storage system where the data is copied to the third storage area and, in addition, the data with update information thereof are copied to the fourth storage area, b) a second copy procedure, according to a second copy pair being formed between the first storage area and the sixth storage area, in which the data with update information thereof are to be copied from the second storage area to the fifth storage area in a copy process between the first storage area and the sixth storage area, (2) the second status including: a) a third copy procedure, according to a third copy pair being formed between the third storage area and the sixth storage area, in which the data with update information thereof are to be copied from the fourth storage area to the fifth storage area in a copy process between the third storage area and the sixth storage area; wherein the first copy procedure copies the data to be written in the first storage area to the second storage system using a synchronous remote copy procedure and the second copy procedure copies the data with update information thereof from the second storage area to the fifth storage area using an asynchronous remote copy procedure.