It is common that Internet service hosting centres use several logical pools to assign server resources to different applications, and that they try to achieve the highest total revenue by making efficient use of these resources. In this paper, multi-tiered enterprise systems are modelled as multi-class closed queueing networks, with each network station corresponding to each application tier. In such queueing networks, bottlenecks can limit overall system performance, and thus should be avoided. We propose a bottleneck-aware server switching policy, which responds to system bottlenecks and switches servers to alleviate these problems as necessary. The switching engine compares the benefits and penalties of a potential switch, and makes a decision as to whether it is likely to be worthwhile switching. We also propose a simple admission control scheme, in addition to the switching policy, to deal with system overloading and optimise the total revenue of multiple applications in the h...
James Wen Jun Xue, Adam P. Chester, Ligang He, Ste