A dynamic load balancing method based on network delay for large distributed systems

The authors propose two dynamic load balancing methods which give consideration to network delays in a large-scale, wide-area distributed system. In general in load balancing, the number of candidate computers for transfers increases as the number of computers being used increases, and so efforts are made to improve response time. There is, however, a concern that performance will drop due to delay overhead when candidate destinations for transfers include computers with large delays. Therefore, in this research the authors configure a collection of computers with low network delays as a duster. They then propose a clustered dynamic load balancing method that emphasizes load information within a cluster and delay information when transfers are performed between clusters, and a threshold dynamic load balancing method which restricts process destinations by creating a threshold value with respect to the ratio between the delay required for a process transfer and the average processing request time for a process. The results of a performance evaluation performed using simulations show that each proposed method can greatly improve the average response time compared to methods that do not consider delays. In addition, each method has an environment in which it is thought to be particularly effective given its operational characteristics. (C) 2001 Scripta Technica.