As long as computers continue to get more CPU processing power, data centers need to optimize their power usage. We can do this and maintain the same complexity level as before by using virtualized environments. We can put a large number of small isolated servers, inside a large one and improve a large number of values like the wattage or power consumption, space usage, and resource usage. In this paper, we present a prototype with which we distribute resources between two virtualized servers, one with Tomcat and another with Globus, and both sharing the same host. The prototype is able to maintain the required SLA and QoS using prediction with simulation in real time. Our goal is to demonstrate that we can use simulation to improve resource management decisions.