Patent ID: 7266718

Claim:
A computer system comprising: a first storage apparatus located at a first site; and a second storage apparatus located at a second site operatively connected to the first site via a network; wherein the first storage apparatus is configured to sort data stored in the first storage apparatus into groups which are each assigned a priority level, and to transfer the sorted data to the second storage apparatus according to the priority, wherein, when a failure occurs in the first storage apparatus, the second storage apparatus transfers the sorted data stored therein, in an order according to the priority levels assigned to the groups, to the first storage apparatus to recover the first storage apparatus, wherein sorted data having a highest priority level is transferred from the second storage apparatus to the first storage apparatus, wherein sorted data having the highest priority level is transferred from the first storage apparatus to the second storage apparatus using synchronous remote copy, and wherein sorted data having priority level other than the highest priority level is transferred from the first storage apparatus to the second storage apparatus using asynchronous remote copy.