US Patent 7577158 Information processing system and access method

A plurality of logical units are set in an information processing device and a storage device and connected by logical paths. The information processing device monitors the path state. When a state change of a path has occurred, the information processing device searches for a normal path connected to the logical unit and decides a logical unit to be an object of the read request. The information processing device issues a data read request to the logical unit decided. Moreover, when a failure has occurred in the path, the information processing device performs an access to the logical unit by utilizing a path other than the path where the failure has occurred and another path sharing a part of the path where the failure has occurred.