Recently, demands are increasing for the further improvement of processing performance of storage systems, along with the enhancement of processing performance of processors and the advancement of data transmission technology. In order to improve the processing performance of the storage system, it is necessary to adopt the latest component technology, to enhance processors and other components, and to improve the processing efficiency of data transfer that occurs within the storage system.
On the other hand, in order to follow the cost reduction advancing throughout the whole storage system market, approaches are made to adopt the latest component technology and the enhancement of components, but such approaches for enhancing the processing performance lead to increased costs, it is difficult to follow market trends. In order to realize both low costs and enhanced processing performance of storage systems, it is effective to improve the processing efficiency of data transfer.
Patent literature 1 discloses an art for enhancing the processing efficiency of data transfer in a storage system. This patent literature teaches efficient use of channel access paths among channel I/F units, disk I/F units and shared memory units or cache memory units, according to which the memory access throughput, especially the access throughput to the cache memory, is improved.