1. A load balancer, comprising: a plurality of request processing units, each of the plurality of request processing units comprising: a network socket that is connected to at least one application server and at least one cache server, and a programmable processor configured to process a cache request from one of the at least one application server; a performance checking unit configured to measure processing loads of the programmable processors; and a processor managing unit configured to adjust the processing loads by writing or deleting a load balancing program in at least one of the programmable processors.