Hitachi, Ltd.

Takashi Itoyama

Yoshifumi Mimata

Ikuya Yagisawa

Susumu Fujii

In order to eliminate I/O performance bottleneck of a path in a disk array system, one expander is composed of two internal expanders connected to each other, and when the path falls in a bottleneck, connection of two internal expanders in a designated expander is cut off, and the cut-off internal expanders are connected to a new path to change access route to the disk drive. A device management table managing individual disk drives and a routing table managing access routes of respective paths are updated according to the switching of the access route.

Access route switching method in disk array system

Deterioration of performance due to diagnosis processing performed when a failure occurs is prevented. A storage apparatusincludes a controllerA and a plurality of expandersA,A coupled to the controllerA to form a first system, and includes a controllerB and a plurality of expandersB,B coupled to the controllerB to form a second system. The controllerA accesses the storage drivethrough the expandersA,A, and the second controllerB accesses the storage drive through the expandersB,B. In the storage apparatus, the controllerA stores a maximum number (concurrently-executable maximum number) of communication portsthat are concurrently diagnosable in the first system, and repeatedly executes a process of selecting the communication portsnot exceeding the concurrently-executable maximum number and a process of causing the expandersA,A to diagnose the selected communication ports

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Tokyo, Japan

Takashi Itoyama