Patent ID: 7363461

Claim:
A storage system, comprising: a first storage device coupled to a first information processing device and having a first disk controller and a plurality of first disk drives, said first disk controller forming a first logical volume related to a first portion of said first disk drives and forming a second logical volume related to a second portion of said first disk drives; and a second storage device coupled to said first storage device and having a second disk controller and a plurality of second disk drives, said second disk controller forming a third logical volume related to a third portion of said second disk drives and forming a fourth logical volume related to a fourth portion of said second disk drives; wherein said first disk controller and said second disk controller manage functions of said first logical volume, said second logical volume, said third logical volume and said fourth logical volume, wherein said first disk controller and said second disk controller perform a first asynchronous remote copy process according to a first status in which said first logical volume functions as a primary logical volume which stores data sent from said first information processing device, said second logical volume functions as a logical volume which stores data, corresponding to updated data stored in said first logical volume as said primary logical volume and to be transferred to said second storage device, said fourth logical volume functions as an auxiliary logical volume, which forms a pair relationship with said first logical volume as said primary logical volume and stores data corresponding to data stored in said first logical volume as said primary logical volume, and said third logical volume functions as a logical volume which stores data corresponding to at least one data of said fourth logical volume as said auxiliary logical volume, wherein said first disk controller and said second disk controller perform a second asynchronous remote copy process according to a second status in which said fourth logical volume functions as a primary logical volume which stores data, said third logical volume functions as a logical volume which stores data, corresponding to updated data stored in said fourth logical volume as said primary logical volume and to be transferred to said first storage device, said first logical volume functions as an auxiliary logical volume, which forms a pair relationship with said fourth logical volume as said primary logical volume and stores data corresponding to data stored in said fourth logical volume as said primary logical volume, and said second logical volume functions as a logical volume which stores data corresponding to at least one data of said first logical volume as said auxiliary logical volume, wherein said first disk controller and said second disk controller are changed from said first status to said second status based on one or more commands.