A disk array apparatus including a storage unit and a storage control unit for controlling storing of data to said storage unit, and being controllable in RAID format, the apparatus comprising:
- said storage control unit configured by interconnecting control packages including boards,
- wherein each of said control packages comprises a base package serving as a base for interconnection and a plurality of functional packages hierarchically connected to said base package, individually separate functions being mounted on each of the plurality of functional packages,
- said base package includes a first junction for said interconnection, a second junction coexisting with and capable of connecting a plurality of different kinds of said functional packages, and an intra-package connection network for communicating between said functional packages and with said storage control unit,
- each of said functional packages includes a junction for being connected to said base package, and
- said storage control unit is configured to perform a processing including a transfer of said data by using communication between said functional package and said base package and communication between said base packages,
- wherein said storage control unit further comprises a global cache memory coupled to each of said control packages via said intra-package connection and configured to be used for caching data during data transfer,
- wherein said controller packages includes a first controller package and a second controller package,
- said first controller package includes a first plurality of I/F packages and a first memory package as said functional packages, said first plurality of I/F packages includes an I/F package, which is coupled to an external device corresponding to a first I/F protocol and is configured to perform communication protocol treatment with the external device according to said first I/F protocol, and an other I/F package, which is coupled to a external device corresponding to a second I/F protocol and is configured to perform communication protocol treatment with the external device according to said second I/F protocol, and wherein said first memory package mounts a first local cache memory used to caching data during data transfer,
- said second controller package includes a second plurality of I/F packages and a second memory package as said functional packages, said second plurality of I/F packages includes an I/F package, which is coupled to an external device corresponding to a first I/F protocol and configured to perform communication protocol treatment with the external device according to said first I/F protocol, and an other I/F package, which is coupled to a external device corresponding to a second I/F protocol and configured to perform communication protocol treatment with the external device according to said second I/F protocol, and wherein said second memory package mounts a second local cache memory configured to be used for caching data during data transfer,
- wherein said control unit is configured to cache data in said first local cache memory during data transfer based on a first access request from a first host computer being coupled to one of said first plurality of I/F packages to a first storage unit being coupled to one of said first plurality of I/F packages,
- said control unit is configured to cache data in said global cache memory during data transfer based on a second access request from said first host computer to a second storage unit being coupled to one of said second plurality of I/F packages.