Method and system for double-machine hot backup

The invention discloses a method and a system for double-machine hot backup. The method comprises the following steps: an aging output-caching module is adopted to be matched with a concentrator; under normal condition, a main machine receives data packets sent by the concentrator and carries out treatment and reinjection processes; a spare machine is under a standby state and caches the data packets firstly broadcasted by the concentrator; when the spare machine receives the data packets reinjected by the main machine, the cache hit succeeds, and the cache is deleted; when the main machine works normally while the reinjection of the data packets is abnormal, flow reinjection of the main machine fails, the spare machine only caches the data packets firstly broadcasted by the concentrator;the aging output-caching module reinjects the data packets according to the thread polling strategy, and the packet loss prevention is ensured during network application process; and when the machineworks abnormally, the spare machine detects the failures of the main machine in a real-time manner, and the spare machine completes the switching process and replaces the main machine for continuous operation.