DOUBLE UPDATE PREVENTION SYSTEM AND DOUBLE UPDATE PREVENTION METHOD

摘要

PROBLEM TO BE SOLVED: To prevent the double update of shared data.SOLUTION: A shared disk device 30 stores a first exclusive flag (a) and a second exclusive flag b indicating an access request state or an access non-request state to shared data, which can be respectively updated only by a first server 10 and a second server 20 in the different partitions of a shared data storage part 301. The first server 10 and the second server 20 acquire exclusive flags (the second exclusive flag b and the first exclusive flag (a)) for the other server from the shared data storage part 301, and perform access to the shared data when the exclusive flags for the other device indicate the access non-request state.