1. A method for managing a plurality of instances of a Wide Area Network (WAN) optimizer executing on an intermediary device, the method comprising: (a) establishing, by a device intermediary to a plurality of clients and a plurality of servers, a plurality of instances of a Wide Area Network (WAN) optimizer on the device to accelerate via compression WAN communications between the plurality of clients and the plurality of servers, the device establishing a configuration of a size of each of the plurality of instances of the WAN optimizer based on data stored from monitoring of previous execution of the plurality of instances of the WAN optimizer; (b) monitoring, by the device, network traffic traversing the device for each of the plurality of instances of the WAN optimizer; and (c) selecting, by a manager executing on the device responsive to the monitoring, a change of a load balancing scheme to load balance the plurality of instances of the WAN optimizer on the device; and (d) automatically changing, by the manager responsive to the monitoring, at least one of the number of instances of the WAN optimizer executing on the device or a size of resource usage of the device used by one or more of the plurality of instances of the WAN optimizer.