GangSim: a simulator for grid scheduling studies

摘要

Large distributed grid systems pose new challenges in job scheduling due to complex workload characteristics and system characteristics. Due to the numerous parameters that must be considered and the complex interactions that can occur between different resource allocation policies, analytical modeling of system behavior appears impractical. Thus, we have developed the GangSim simulator to support studies of scheduling strategies in grid environments, with a particular focus on investigations of the interactions between local and community resource allocation policies. The GangSim implementation is derived in part from the Ganglia distributed monitoring framework, an implementation approach that permits mixing of simulated and real grid components. We present examples of the studies that GangSim permits, showing in particular how we can use GangSim to study the behavior of VO schedulers as a function of scheduling policy, resource usage policies, and workloads. We also present the results of experiments conducted on an operational Grid, Grid3, to evaluate GangSim's accuracy. These latter studies point to the need for more accurate modeling of various aspects of local site behavior.