Patent ID: 7743211

Claim:
A storage system comprising: a protocol transformation unit connected to an external device and including a first processor which controls transferring a read/write request sent from an external device; a hard disk device; a disk adapter that connects to said hard disk device and including a second processor which controls transferring a data to/from said hard disk device; a plurality of cache adapters, each of said cache adapters is configured independently from said disk adapter; and, an interconnection network, which is connected to said protocol transformation unit, said disk adapter, and said cache adapters; wherein at least two cache adapters of said cache adapters are configured into a cluster, wherein said each cache adapter has a third processor, a cache memory that stores a copy of at least some of said data stored in said hard disk device, wherein said third processor in each of said at least two cache adapters is configured to access cache memories in said at least two cache adapters which configures said cluster, and conducts cache hit/miss control based on said read/write request sent from said protocol transformation unit, and when said third processor determines that a cache miss occurs, said third processor sends a request to retrieve, requested data from said hard disk device to said disk adapter through said interconnection network, and sends said retrieved data to said protocol adapter through said interconnection network.