Patent ID: 8078764

Claim:
An information processing system, comprising: a physical server including a processor and a memory; a virtualization module for virtualizing a computer resource of the physical server to execute a virtual server; the physical server comprises a plurality of the physical servers for executing the virtual server; and an I/O switch for connecting the plurality of physical servers with one or more I/O devices, the virtualization module being configured to perform a migration of the virtual server, the I/O switch including: a register for storing inhibition instruction information for instructing an inhibition of an issuance of a transaction from the I/O device to the virtual server; a transaction inhibition control module for inhibiting, when the inhibition instruction information is stored into the register, the issuance of the transaction from the I/O device to the virtual server to be migrated, and guaranteeing a completion of a transaction issued from the I/O device before the inhibition of the issuance of the transaction; a virtualization assist module including an address conversion unit for retaining an association between a memory address of the virtual server and an address thereof within the memory of the physical server that executes the virtual server, for converting the memory address of the virtual server into the address thereof within the memory of the physical server; and a switch management module for managing a configuration of the I/O switch, the virtualization module including: an I/O device management module for managing an association between the virtual server on the physical server and the I/O device allocated to another virtual server; a transaction instruction module for identifying the I/O device allocated to a migration-subject virtual server from the I/O device management module, and setting and canceling the inhibition instruction information with respect to the register of the I/O switch correspondent to the I/O device; and a configuration change instruction module for instructing the switch management module to change the configuration of the I/O switch, and issuing a command for a change in the address of the physical server to the address conversion unit managed by the virtualization assist module, wherein the transaction instruction module is configured to: set, at a start of the migration, the inhibition instruction information in the register, and inhibit the issuance of the transaction from the I/O device to the migration-subject virtual server; and cancel, when the migration is completed, the inhibition instruction information set in the register, and permit the issuance of a transaction from the I/O device to the virtual server toward which the migration has been completed.