A system, computer program product and computer-implemented method of dynamically adding a best suited application server to a cluster of application servers are provided. To do so, a history of quality of service (QoS) of a plurality of application servers is maintained. Using the history of QoS, an application server is dynamically selected and added to the cluster when the cluster is under a heavy workload. The selected application server is one that has the most historically favorable QoS and a heavy workload is one that exceeds a user-configurable threshold.