Patent ID: 7660918

Claim:
A method of controlling enablement/disablement of I/O requests from plural host computers to a disk device, said method comprising: in said host computers, transmitting access-right change commands to said disk device, said access-right change commands including one piece or plural pieces of information having I/O-enable/disable information and host identification information to correspond to each other in a one-to-one correspondence manner, said I/O-enable/disable information indicating whether or not said disk device will execute said I/O requests from said host computers, said host identification information identifying said respective host computers, and issuing, to said disk device, said I/O requests to which said host computers have added said host identification information; and in said disk device, changing entirely said I/O-enable/disable information for each of said host computers relating to the plurality of I/O requests for plural paths held by each of said host computers between said host computers and said disk device in response to a single transmission of one of said access-right change commands from one of said host computers, and storing and holding said I/O-enable/disable information in an access-right management table, identifying request-source host computers in response to said I/O requests from said host computers, and, based on said host identification information and said I/O-enable/disable information held in said access-right management table, enabling or disabling said I/O requests to be executed on each host-computer's node basis.