Patent ID: 7412576
Filing Date: 2008-08-12
Classification: G06F

Abstract:
1. A remote copy system, comprising: a first storage system including a first storage controller and a first data volume, the first storage controller being configured to control data access requests to the first data volume, the first storage system being configured to store write data in the first data volume upon receiving a write request from a first host that is associated with the first storage system; a second storage system including a second data volume and configured to receive first copy data sent from the first storage system and store the first copy data in the second data volume, the first copy data corresponding to the write data stored in the first data volume; a third storage system including a second storage controller and a third data volume and configured to receive second copy data from the second storage system and store the second copy data to the third data volume, the second copy data corresponding to the first copy data, the third data volume mirroring the first data volume; a fourth storage system including a fourth data volume and configured to receive third copy data sent from the third storage system and store the third copy data to the fourth data volume, the third copy data corresponding to the second copy data and configured to perform a reverse replication operation wherein the reverse replication operation includes realizing at the first storage system that the third storage system has been converted to a production site; establishing links between the first storage controller and the first data volume located in the first storage system; reestablishing a link between the first and the second storage systems; determining a storage controller pointer to be transferred between the fourth data volume and the first storage controller based on a JSUS mark; including a journal in the first storage system to receive a transfer of a journal process from a journal of the fourth storage system; transferring a journal process between the journal of the fourth storage system and a journal of the first storage system; applying the journal process to the first data volume, and synchronously taking a journal process to a journal of the second storage system; 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 storing the write data to the first data volume and sending the first copy data to the second storage system are performed synchronously, wherein the second storage system transmits the second copy data to the third storage system asynchronously from the storing the write data to the first data volume.