Patent ID: 7689792
Filing Date: 2010-03-30
Classification: G06F

Abstract:
1. A storage system comprising: a plurality of storage control units; and a plurality of disk devices each of which is coupled to one of the plurality of storage control units, wherein, if a first storage control unit receives a write request from a computer while data copy is performed from a first disk device coupled to the first storage control unit to a second disk device coupled to a second storage control unit, the first storage control unit determines whether a target area of the write request is copied or not, wherein, if the target area of the write request has been already copied, the first storage control unit sends the write request to the second storage control unit, and the first and second storage control units respectively write data of the write request to the first and second disk devices, wherein, if the target area of the write request has not been copied yet, the data of the write request is written to the first disk device, wherein the data copy is performed by a predetermined data size and whether the data is copied or not is managed in a unit of a predetermined data size, and wherein, if the target area of the write request has not been copied yet, the second storage control unit compares the target area of the write request with a not-copied area managed in the unit of the predetermined data size, and the second storage control unit does not issue a to-be written request if the target area in the write request coincides with the not-copied area.