Patent ID: 7801026

Claim:
A virtualization switch comprising: a plurality of first communication line connection terminals which can be connected to a host computer, a single physical storage apparatus or a plurality of physical storage apparatuses, and another virtualization switch by first communication lines; a second communication line connection terminal which can be connected to a single line concentrator or a plurality of line concentrators connected to a manager computer by a second communication line; and storage virtualization unit which causes the host computer to recognize a storage area obtained by combining some or all of storage areas of the single physical storage apparatus or the plurality of physical storage apparatuses as a virtual storage apparatus, the virtualization switch further comprising: first communication unit which can communicate with the other virtualization switch through the first communication line; second communication unit which can communicate with the other virtualization switch through the second communication line and the line concentrator; second communication line monitor unit which periodically performs test communication to check whether communication with the other virtualization switch can be performed by the second communication unit and which detects whether the second communication line on its own apparatus side between the virtualization switch and the line concentrator is abnormal when abnormal communication is detected during the test communication; and abnormal state coping unit which operates when the second communication line monitor unit detects the abnormal communication, wherein when the second communication line monitor unit detects abnormal communication with the other virtualization switch and detects that the abnormality is abnormality of the second communication line on its own apparatus side, the abnormal state coping unit executes a closing process which closes an access between the host computer and the physical storage apparatus through the virtualization switch and causes the first communication unit to output a failover designation instruction which causes the other virtualization switch to execute a failover process, and when the second communication line monitor unit detects abnormal communication with the other virtualization switch and detects that communication of the second communication line on its own apparatus side is normal, the abnormal state coping unit executes the failover process and causes the first communication unit to output a closing designation instruction which executes a closing process for closing an access between the host computer and the physical storage apparatus through the other virtualization switch.