Patent ID: 7457899

Claim:
A first storage control apparatus adapted to be coupled to a second storage control apparatus comprising second plurality of storage devices and executing data read/write processes to said second plurality of storage devices based on a Redundant Array of Independent Disks (RAID) scheme, said first storage control apparatus comprising: a cache memory; a first plurality of storage devices; said first storage control apparatus receiving a first data write request, storing first data corresponding to said first data write request in said cache memory, transmitting a first completion notice of said first data write request, and executing a data write processes of said first data stored in said cache memory to said first plurality of storage devices provided with a first logical volume, having a first Logical Unit Number (LUN), of said first storage control apparatus; and said first storage control apparatus receiving a second data write request, storing second data corresponding to said second data write request in said cache memory, transmitting a third data write request corresponding to said second data write request to said second storage control apparatus by referring to mapping information between a second LUN, designated by said second data write request, and a third LUN of a second logical volume to which said second storage control apparatus executes a data write process of said second data, wherein said first storage control apparatus transmits a second completion notice of said second data write request without waiting for a third completion notice from said second storage control apparatus, said third completion notice corresponding to the said third data write request, wherein when said first storage control apparatus receives a first data read request, said first storage control apparatus transmits a second data read request corresponding to said first data read request to said second storage control apparatus by referring to said mapping information.