Patent ID: 7529885

Claim:
A cache control method in a computer system that includes a storage device having a plurality of physical devices for storing data, at least one client, and a relay device, the cache control method comprising: relaying, by said relay device, data between said storage device and each of said at least one client, wherein said relay device includes a cache disk module for caching processed data being relayed between said storage device and said at least one client; relating data processed in the computer system with attribute data which configures a caching operation of the cache disk module that caches the processed data on a primary network which connects each of said at least one client and said relay device to each other; and mediating the processed data between the storage device and each of the at least one client via a secondary network, which connects said relay device and said storage device to each other, without the caching operation of the cache disk module when the attribute data prohibits the caching operation, wherein a plurality of virtual volumes are formed on said physical devices, and each of said at least one client is assigned to at least one of said virtual volumes, thereby permitting said each of said at least one client to access data stored in said at least one of said virtual volumes to which it is assigned, wherein said attribute data is stored in a cache attribute management table which stores a plurality of entries, each of which sets a corresponding relation between identification information identifying one of said virtual volumes, identification information identifying at least two of said physical devices forming a part of said one of said virtual volumes, and said attribute data, which provides an indication whether data stored in said one of said physical devices is cacheable or not, wherein said attribute data corresponding to each of said at least two of said physical devices may differ from one another, wherein each entry of said cache attribute management table further sets a corresponding relation between an indication as to whether data to be read from each of said at least two of said physical devices forming part of said one of said virtual volumes is cacheable or not and an indication as to whether data to be written to each of said at least two of said physical device forming part of said one of said virtual volumes is cacheable or not, and wherein when one physical device of said at least two of said physical devices is shared by a first virtual volume and a second virtual volume, said attribute data corresponding to said first virtual volume indicates that data stored in said one physical device is cacheable, and said attribute data corresponding to said second virtual volume indicates that data stored in said one physical device is not cacheable.