1. A method for load balancing between WAN optimization devices, the method comprising: determining a mapping based on capacities of a set of remote WAN optimization devices and capacities of a set of local WAN optimization devices, wherein the mapping maps each remote WAN optimization device to a local WAN optimization device; directing connection requests from the set of remote WAN optimization devices to the set of local WAN optimization devices based on the mapping; measuring performance metrics for the set of local WAN optimization devices; modifying the capacities of one or more local WAN optimization device based on the measured performance metrics; modifying the mapping based on the modified capacities; and directing connection requests from the set of remote WAN optimization devices to the set of local WAN optimization devices based on the modified mapping.