Patent ID: 7770062

Claim:
A redundancy system in which when service performing data provided in an ACT server is changed, the changed data is transmitted to a SBY server, wherein said ACT server comprises: synchronization data management means, disposed in a shared memory in said ACT server, for managing of synchronization data with respect to each of segments of a synchronization data memory; synchronization request information setting means for, on the occurrence of synchronization data change, setting synchronization request data for a changed one of said segments corresponding to said synchronization data change to said synchronization management means; and transmitting means for transmitting said changed one of said segments to be synchronized to said SBY server on the basis of said synchronization request information set to said synchronization data management means; wherein said synchronization data management means includes a synchronization memory area for storing said synchronization data with respect to each of said segments, a synchronization request management section for managing the presence or absence of the synchronization request for said each of segments in the synchronization memory area, a synchronization request information holding section for holding said synchronization request information set by said synchronization request information setting means; and wherein said transmitting means monitors at a given timing said synchronization request information holding section, and reads and then transmits said segments in said synchronization memory area on the basis of the synchronization request information held in said holding section.