Server load balancing (SLB) is the process of deciding to which server a load-balancing device should send a client request for service. For example, a client request may consist of an HTTP GET for a web page or an FTP GET to download a file. The job of the load balancer is to select the server that can successfully fulfill the client request and do so in the shortest amount of time without overloading either the server or the server farm as a whole.