Patent ID: 7472240

Claim:
A storage system comprising: a plurality of storage nodes each including at least one storage device configured to store data and plural control devices, each control device comprising: a network controller for communication with a host computer; a disk controller coupled to the at least one storage device for controlling input and output of data for the at least one storage device; and a memory for storing control information used for input and output of data with the at least one storage device; and a control device coupling unit configured to connect control devices from among mutually different ones of the storage nodes without using access paths between the control devices and any host computers, each of the control devices configured to access a combined memory area having a single address space, the combined memory area comprising the memories of each of the control devices, wherein each of the control devices among the storage nodes in the storage system is associated with a control device affiliation such that each of the control devices in a storage node is associated with a different control device affiliation, and the control device coupling unit connects only those control devices among the storage nodes that are associated with the same control device affiliation.