Patent ID: 7921269
Filing Date: 2011-04-05
Classification: G06F

Abstract:
1. A first storage subsystem of a storage system, said storage system comprising the first storage subsystem and a second storage subsystem, said first storage subsystem comprising: a first memory device, wherein said second storage subsystem comprises a second memory device, and wherein the first storage subsystem is communicably connected to a host device for sending write requests and write target data and is communicably connected to said second storage subsystem; a disk controller for writing said write target data from said host device in said first memory device, wherein said disk controller comprises a processor and a cache memory for temporary storage of said write target data exchanged between said host device and said first memory device; a pre-updated data memory region for storing data that constitutes data prior to update by the write target data and constitutes data that has been written in said first memory device, wherein said pre-updated data memory region is a third memory device that can be configured as a pair with said first memory device; a first type logical volume, provided in a physical memory device, for which no specific attributes are set; and a plurality of second type logical volumes, provided in a physical memory device, for which specific attributes are set, wherein said first memory device and said second memory device constitute said first type logical volume, wherein said third memory device constitutes a virtual logical volume configured from at least one of the second type logical volumes, and wherein said disk controller, by writing said write target data in a second type logical volume of said plurality of second type logical volumes that has a free space, writes said write target data in said virtual logical volume.