Clusters of computers have emerged as cost-effective parallel and/or distributed computing systems for computationally intensive tasks. Normally, clusters are composed of high performance computational nodes linked together by low-latency/high-bandwidth interconnection networks. With the advent of modern optical networking technologies, geographically distant clusters can be federated to yield systems considered tightly-coupled. By using Service Address Routed (SAR) optical networks, cluster federations are shown to be effective in dealing with complex scientific computations in a manner that is transparent to the user. The analysis of such federated clusters is carried out using a discrete event simulator. The findings include means to control the tradeoff between user response time and overall completion time, the advantages and disadvantages of exploiting and giving up locality, and how a meticulous control over the level of greediness can yield noticeable performance improvement...
Isaac D. Scherson, Daniel S. Valencia, Enrique Cau