PURPOSE: To execute most appropriate restoring operation without intervention of an operator by more concretely identifying a place generating a fault within a system by a monitoring element in a computer system.

CONSTITUTION: The computer system is equipped with plural duplicated units 10 and 11. At least two of these units 10 and 11 include the monitoring element for monitoring the state of the system. These monitoring elements mutually communicate so as to exchange state information so that both of these monitoring elements can form a view point obtained by combining the states of the system based on information collected by both monitoring elements.