DISTRIBUTED SYSTEM AND REDUNDANCY CONTROL METHOD

A distributed system using a quorum redundancy method in which a redundancy process is executed by at least Q processing elements of N processing elements communicable with each other, each of N processing elements includes a resynchronization determining unit for determining that an execution state of the processing element itself can be resynchronized with a latest execution state in the distributed system in the case where the processing element can communicate with at least F+1 elements (F=N−Q) already synchronized of the N processing elements at the time of rebooting the processing element, and a resynchronizing unit for resynchronizing the execution state of the processing element itself to the latest one of the execution states of the at least F+1 processing elements in accordance with the result of determination by the resynchronizing unit.