Patent ID: 7624230

Claim:
An information processing system, comprising: a storage apparatus comprising: storage devices for providing logical devices to store data; and a first processing unit providing virtual logical units based on a mapping relation between the logical devices and the virtual logical units and being operative to switch the mapping relation dynamically according to an external request; and a file sharing server comprising; a cache memory including cache extents; and a second processing unit operative to provide the virtual logical units of the storage apparatus to a host system by using said cache extents, and manage the mapping relationships between the logical devices and the virtual logical units; wherein said second processing unit is operative to request a certain file from the storage apparatus, read data of the certain file from the corresponding logical device in said storage apparatus and store said data in one of the cache extents of the cache memory, and perform data I/O processing to data of said file stored in said cache extent according to a file access request given by said host system for accessing said file.