Patent ID: 7337281

Claim:
A storage system, comprising: at least one channel adapter package having multiple channel adapters each for performing data communication with one or more host devices; each of the multiple channel adapters comprising: two or more processors for controlling the data communication with the host devices; a local cache memory for temporarily storing data accessed by the host devices, an internal bus for connecting the two or more processors and the local cache memory and for allowing faster data transmission than that of a connection network, multiple storage devices for storing data in a RAID disk array; multiple storage adapters each for performing data communication with the multiple storage devices; a main cache memory for temporarily storing data exchanged between the multiple channel adapters and the multiple storage adapters; and the connection network for connecting the multiple channel adapters and the multiple storage adapters to the main cache memory, wherein each of the processors can directly access the local cache memory through the internal bus within each of the channel adapters; wherein, when each of the processors within each of the channel adapters receives write-data and a write-request with respect to the write-data from the host device, the write data is written in the local cache memory, directory information for locating the storage area of the write-data in the storage device is stored, a response to the write-request is sent to the host device, and the write-data is transferred from the local cache memory to the main cache memory through the connection network such that the write-data can be written in the storage device by the storage adapter, wherein each of the processors writes the write-data in the local cache memory and stores the directory information of the write-data synchronously to a process from the receipt of the write-request to the transmission of the response to the host device, and transfers the write-data from the local cache memory to the main cache memory by a back-write caching method asynchronously to the process from the receipt of the write-request to the transmission of the response to the host device, wherein the multiple channel adapters are mounted on the channel adapter package, and the multiple channel adapters are connected to each other through the internal bus such that the local cache memory of each of the multiple channel adapters on the channel adapter package is used as distributed local cache memory, and on the channel adapter package, each of the processors within the multiple channel adapters can directly access not only the local cache memory within the same channel adapter but also the local cache memory within another channel adapter on a same said channel adapter package through the internal bus; and wherein the connection network has a construction in accordance with a hierarchical starnet architecture.