Patent ID: 7373470
Filing Date: 2008-05-13
Classification: G06F

Abstract:
1. A storage system that includes a first storage subsystem having a first storage area and multiple second storage subsystems that each include a second storage area for storing duplicate data for data stored in the first storage area; wherein the first storage subsystem comprises: a writing module that executes a write process by which write data is written to the first storage area; a copy information transmission module that, in conjunction with the write process, sends copy information to the second storage subsystems, wherein the copy information is used to copy the write data to the second storage areas; a section establishment module that establishes a write section for each write process, wherein the write section is a temporal section to which the copy information corresponding to the write process belongs; and a section information transmission module that transmits section information to the second storage subsystems, wherein the section information indicates the write section to which the copy information belongs; and wherein the second storage subsystems each comprise: a copy execution module that executes a copy process corresponding to the write process using the copy information; and a history creation module that creates history information using the section information for each write section that the copy information used in the copy process belongs to, wherein the history information includes history of each executed copy process, wherein the history information created for each write section includes a map that records whether data has been changed due to the copy process for each of multiple sub-storage areas, wherein the second storage area is divided into the multiple sub-storage areas.