Storage control unit with control signal path between coupled controllers

A storage control unit comprising:

• a storage unit including a plurality of storage devices;
• a first control unit and a second control unit that perform data input/output processing for the storage unit in response to a data input/output request from a host, the first control unit including a first controller that performs the overall control of the data input/output processing, and a first initiator that performs control to access a storage device, from among the plurality of storage devices in the storage unit, that is the target for the data input/output request based on the data input/output request, the second control unit including a second controller that performs the overall control of the data input/output processing, and a second initiator that performs control to access a storage device, from among the plurality of storage devices in the storage unit, that is the target for the data input/output request based on the data input/output request, the first controller and the second controller being connected via a control signal path that can send/receive control data;
• a first connection path that connects the first control unit and the storage unit;
• and
• a second connection path that connects the second control unit and the storage unit,
• wherein the first controller in the first control unit, based on the data input/output request from the host system targeting the storage unit, issues the data input/output request to the second initiator in the second control unit using the control signal path, and accesses the target storage device via the second connection path based on the data input/output request, and
• wherein, upon occurrence of a failure in access from a control unit from among the first and second control units to the storage unit, the control unit sends the data input/output request to the other control unit from among the first and second control units via the control signal path.

A storage control unit comprising two channels, each including:

• a storage unit;
• a control unit that performs data input/output processing for the storage unit in response to a data input/output request from a host;
• and
• a connection path connecting the control unit and the storage unit,
• wherein when a failure occurs in the connection path in one of the two channels and the data input/output request from the host is issued to the control unit in that failed channel, the control unit transfers the data input/output request to the control unit in the other channel and the control unit in the other channel accesses the storage unit via the connection path in the other channel, and
• wherein the control unit in the one channel, triggered by the occurrence of an access failure when the control unit accesses the storage unit via the connection path in the channel, transfers the data input/output request from the host to the control unit in the other channel.