Remote copy system having multiple data centers

A method for operating a remote copy system having a first storage system with a first primary volume and first journal volume, a second storage system with a second primary volume and second journal volume, a third storage system with a third primary volume and third journal volume, and a fourth storage system with a fourth primary volume and fourth journal volume, the method comprising:

• at the first storage system realizing that the third storage system has been converted to a production site;
• establishing links between the first journal volume and the first primary volume located in the first storage system;
• reestablishing a link between the first and the second storage systems;
• determining a journal volume pointer to be transferred between the fourth journal volume and the first journal volume based on a JSUS mark;
• transferring a journal process between the fourth journal volume and the first journal volume;
• applying the journal process to the first primary volume, and synchronously taking a journal process into the second journal volume;
• wherein the first storage system and the second storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities;
• wherein the second storage system and the third storage system are placed sufficiently far apart to prevent both the second and third storage systems from damage at the same time due to a regional disaster;
• wherein the third storage system and the fourth storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities at the first storage system;
• wherein the fourth storage system and the first storage system are placed sufficiently far apart to avoid both the fourth and first storage systems from being destroyed at the same time due to a regional disaster;
• and
• wherein first data communication between the first and second storage systems is based on a synchronous remote copy method, and second data communication between the second and third storage systems is based on an asynchronous remote copy method, and third data communication between the third and fourth storage systems is based on a synchronous remote copy method.

A computer readable medium including a computer program for operating a remote copy system having a first storage system with a first primary volume and first journal volume, a second storage system with a second primary volume and second journal volume, a third storage system with a third primary volume and third journal volume, and a fourth storage system with a fourth primary volume and fourth journal volume, the computer program comprising:

• a code for realizing at the first storage system that the third storage system has been converted to a production site;
• a code for establishing links between the first journal volume and the first primary volume located in the first storage system;
• a code for reestablishing a link between the first and the second storage systems;
• a code for determining a journal volume pointer to be transferred between the fourth journal volume and the first journal volume based on a JSUS mark;
• a code for transferring a journal process between the fourth journal volume and the first journal volume;
• a code for applying the journal process to the first primary volume, and synchronously taking a journal process into the second journal volume;
• and
• wherein the first storage system and the second storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities;
• wherein the second storage system and the third storage system are placed sufficiently far apart to prevent both the second and third storage systems from damage at the same time due to a regional disaster;
• wherein the third storage system and the fourth storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities at the first storage system;
• wherein the fourth storage system and the first storage system are placed sufficiently far apart to avoid both the fourth and first storage systems from being destroyed at the same time due to a regional disaster;
• and
• wherein first data communication between the first and second storage systems is based on a synchronous remote copy method, and second data communication between the second and third storage systems is based on an asynchronous remote copy method, and third data communication between the third and fourth storage systems is based on a synchronous remote copy method.

A storage system provided in a remote copy system, wherein the remote copy system includes a first storage system with a first primary volume and first journal volume, a second storage system with a second primary volume and second journal volume, a third storage system with a third primary volume and third journal volume, and a fourth storage system with a fourth primary volume and fourth journal volume, the storage system comprising:

• a storage unit including a plurality of storage disks that define a plurality of storage volumes;
• a storage controller to control access to the storage unit;
• a communication interface coupled to a network;
• and
• a computer readable medium including a computer program for operating the storage system, the computer program including:
• a code for realizing at the first storage system that the third storage system has been converted to a production site;
• a code for establishing links between the first journal volume and the first primary volume located in the first storage system;
• a code for reestablishing a link between the first and the second storage systems;
• a code for determining a journal volume pointer to be transferred between the fourth journal volume and the first journal volume based on a JSUS mark;
• a code for transferring a journal process between the fourth journal volume and the first journal volume;
• a code for applying the journal process to the first primary volume, and synchronously taking a journal process into the second journal volume;
• wherein the first storage system and the second storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities;
• wherein the second storage system and the third storage system are placed sufficiently far apart to prevent both the second and third storage systems from damage at the same time due to a regional disaster;
• wherein the third storage system and the fourth storage system are placed close enough to execute a synchronous remote copy operation with minimal impact on IO processing capabilities at the first storage system;
• wherein the fourth storage system and the first storage system are placed sufficiently far apart to avoid both the fourth and first storage systems from being destroyed at the same time due to a regional disaster;
• and
• wherein first data communication between the first and second remote storage systems is based on a synchronous remote copy technology, and second data communication between the second remote storage system and the storage system is based on an asynchronous remote copy technology, and third data communication between the storage system and the third remote storage system is based on a synchronous remote copy technology.