Information processing apparatus, a method that takes a checkpoint between the main system and the standby system of standby redundant system and the standby redundant system

摘要

PURPOSE:To efficiently enable an inside state transferring processing between a main system and a stand-by system according to the change of the inside state of the main system, and to simplify the detection of the fault of the main system. CONSTITUTION:When messages stored in a received message buffer of the stand-by system reaches a prescribed amount (401), when the messages from the other main systems are not received at all within a fixed time (402), or when the messages transmitted by the corresponding main system are not received at all within the fixed time, are defined as a timing in which a check point for holding the inside states of both the main system and the stand-by system to be the same is set. Thus, the total number of the check points can be reduced, and the check point can be efficiently set. Also, when a response to a check point request is not made even after the lapse of the fixed time, the abnormality of the main system is judged, and the succeeding processing is executed by the stand-by system.