Method and apparatus for reliable disk fencing in a multicomputer system

A computer usable medium having computer readable code embodied therein for preventing access to a shared peripheral device by a processor-based node in a multinode system having a plurality of nodes, the resource being coupled to the system by a resource controller, the computer usable medium comprising:

• a membership monitor module configured to determine a membership list of the nodes including said resource, on the system at predetermined times, including at least at a time when the membership of the system changes;
• a resource manager module configured to determine when the resource is in a failed state and for communicating the failure of the resource to said membership monitor to indicate to the membership monitor to generate a new membership list;
• a configuration value module configured to generate a unique value based upon said new membership list and to store said unique value locally at each node on the system, wherein said configuration value module includes a submodule configured to generate the unique value based upon an epoch number generated by a membership protocol module;
• and
• an access control module configured to block access requests by at least one requesting node to said resource when the locally stored unique value at said requesting node does not equal the unique value stored at said resource controller.