Patent ID: 7930482
Filing Date: 2011-04-19
Classification: G06F

Abstract:
1. A storage system comprising: a first storage apparatus operatively connected to a host computer and providing a first logical device I/O-accessed by the host computer; and at least one second storage apparatus operatively connected to the first storage apparatus and providing a second logical device configured as at least a part of the first logical device, wherein the first storage apparatus comprises: a first disk drive; and a first controller configured to control the first disk drive based on a first I/O access request sent from the host computer, wherein the first controller comprises a first cache memory, intervening between the host computer and the first disk drive, configured to cache, wherein the at least one second storage apparatus comprises: a second disk drive; and a second controller operatively connected to the first storage apparatus and configured to control the second disk drive based on a second I/O access request received from the host computer via the first storage apparatus, wherein the second controller comprises a second cache memory, intervening between the host computer to the second disk drive, configured to cache the data related to the second I/O access request, and wherein the first controller sends, to the second storage apparatus, a residency setting instruction to set a predetermined area in the second cache memory that serves as a resident area, and wherein when the second storage apparatus sets a resident area, the first storage apparatus that has sent the residency setting instruction sends, to the other storage apparatuses, a resident area table for managing the resident areas in the other storage apparatuses.