Automatic switching method of a right of management/control for shared-storage unit

An automatic method for switching a right of management/control for a shared-storage unit between a plurality of service processors in a cluster-coupled system where each cluster is connected to a shared-storage unit via a primary communication path and a service processor selecting register, each cluster of the cluster-coupled system being formed with one of the plurality of service processor, the method comprising the steps of:

• registering a physical number of the service processor which acquires the right of management/control in the service processor selecting register;
• and
• providing a secondary communication path connecting each of the plurality of service processors;
• wherein, when a service processor of a first cluster detects a power-off or a hang-up message from the service processor of the cluster which includes the service processor registered in the service processor selecting register through the secondary communication means, the service processor of the first cluster determines a new physical number of the service processor which acquires the right of management/control based on a predetermined decision theory, and registers the determined physical number in the service processor selecting register.