Abstract: A method for managing virtual machines, the method causing a management server having a database includes link relation information and connected to a plurality of physical servers, on which virtual machine hosts are installed, the method includes updating the link relation information in such a manner that a link between a virtual machine host and a first virtual machine guest is disconnected, when information regarding the first virtual machine guest cannot be acquired from the virtual machine host and updating the link relation information stored in such a manner that a link between a virtual machine host and a second virtual machine guest, when information regarding the second virtual machine guest is acquired from the virtual machine host.

Abstract: A method for managing virtual machines, the method causing a management server having a database includes link relation information and connected to a plurality of physical servers, on which virtual machine hosts are installed, the method includes updating the link relation information in such a manner that a link between a virtual machine host and a first virtual machine guest is disconnected, when information regarding the first virtual machine guest cannot be acquired from the virtual machine host and updating the link relation information stored in such a manner that a link between a virtual machine host and a second virtual machine guest, when information regarding the second virtual machine guest is acquired from the virtual machine host.

Abstract: An I/O control device that transfers data according to transfer control information, comprising a transfer control information memory means that stores transfer control information, a state detecting means that detects the processed state of the transfer control information stored in the transfer control information memory means, and a transfer control information memory control means by which new transfer control information is stored in the transfer control information memory means in place of the transfer control information upon completion of transfer control information-dependent transfer processing as a result of the detection by the state detecting means.

Abstract: A management device creates transmission path connection information from device information which it collects from individual devices. If the management device is notified of a faulty device from a managed device, it identify a transmission path containing the faulty device and causes the server, which accesses data stored in the storage through the transmission path, to stop using the transmission path. To deal with devices not having the failure notice function, the management device can cause individual devices to present device information on a regular basis and detect a faulty device from the received device information. When the transmission path is restored to proper working condition, the management device is notified of the restored path and automatically causes to the server to start using that transmission path. Note that the functions performed by the management device can also be provided as programs.

Abstract: An I/O control device that transfers data according to transfer control information, comprising a transfer control information memory means that stores transfer control information, a state detecting means that detects the processed state of the transfer control information stored in the transfer control information memory means, and a transfer control information memory control means by which new transfer control information is stored in the transfer control information memory means in place of the transfer control information upon completion of transfer control information-dependent transfer processing as a result of the detection by the state detecting means.