Patent ID: 7363535

Claim:
In a clustering system having primary and secondary host computers coupled to a plurality of storage systems and a management computer, wherein the primary and secondary host computers include cluster management functions, wherein each of the plurality of storage systems includes a LUN security function therein so that one or more predetermined host computers of the clustering system can access at least one of a plurality of logical units in a storage system from among the plurality of storage systems, a method comprising: storing access control information in the storage system, in connection with host identification information and logical unit identification information, wherein the LUN security function in the storage system allows the primary host computer to access a specific logical unit of the logical units and disallows the secondary host computer to access the specific logical unit based on the access control information; changing ownership for the specific logical unit from the primary host computer to the secondary host computer by the cluster management functions; based upon ownership information provided by the cluster management functions, coordinating management of security for the specific logical unit in the management computer based on corresponding information to the access control information, the corresponding information to the access control information being stored in the management computer, in connection with storage identification information, the host identification information and the logical unit identification information; and changing the access control information in the storage system, for disallowing the primary host computer to access the specific logical unit and allowing the secondary host computer to access the specific logical unit based upon a request for changing the access control information from the management computer; wherein the request for changing the access control information from the management computer is issued if the secondary host computer takes over processing of the primary host computer.