Storage system and method for automatic restoration upon loop anomaly

An automatic restoration method of a storage system for accessing a plurality of storage devices in response to data access requests from a requesting device, comprising:

• detecting a loop anomaly during accessing of said plurality of storage devices by a controller connected to said plurality of storage devices via a pair of loops;
• issuing, in response to detection of said loop anomaly, an instruction to restore said loop from said controller to a switch circuit having a switch controller and a plurality of port switches, that each of said plurality of port switches connects said loop to each of said plurality of storage devices;
• and
• in response to said instruction from said controller, bypassing all said plurality of port switches to said loop by said switch controller;
• after all of said port switches have been bypassed, creating a loopback path in each of the plurality of said port switches from corresponding storage device of said the plurality of storage devices to the corresponding storage device by parallel operating said plurality of port switches of said switch controller;
• executing an initialization process and sending a signal to said port switch by said storage devices in response to creation of the loopback path in the port switch;
• monitoring the signals in said port switches from said storage devices by said switch controller;
• judging that a storage device that did not send the signal is anomalous to diagnose said storage devices by said switch controller;
• and
• according to the diagnosis results, bypassing said storage device judged to be anomalous from said loop by said switch controller.

A storage system for accessing storage devices according to data access requests from a requesting device, the storage system comprising:

• a plurality of said storage devices;
• a controller that controls access to the plurality of storage devices;
• a loop that exchanges information between the controller and the plurality of storage devices;
• and
• a switch circuit comprising:
• a plurality of port switches that each connects and bypasses the loop to and from each of the plurality of storage devices and creates a loopback path from corresponding storage device of said plurality of storage devices to the corresponding storage device;
• and
• a switch controller that is connected to said loop and is connected parallel to said plurality of port switches and connects and bypasses each of plurality of port switches to and from the loop,
• wherein the controller issues a restoration instruction to the switch circuit to restore the loop, when the controller detects a loop anomaly while accessing said plurality of storage devices, and
• the switch controller, in response to the restoration instruction, forms a plurality of logical loop that each of the plurality of logical loop logically connects each of the plurality of storage devices to the loop by creation of the loopback path in each of the plurality of port switches, diagnoses each of the plurality of storage devices in parallel sequence by judging whether the storage devices execute an initialization process and send a signal in response to formation of the logical loop, and according to the diagnosis results, bypasses an anomalous storage device judged that did not send the signal from the loop.