Evaluation of the inter-cluster data transfer on Grid environment

High-performance peer-to-peer transfer between clusters will be fundamental technology base for various Grid middleware, such as large-scale data transfer in DataGrid settings, or collective communication in Grid-wide MPIs. There, two major factors are involved: on one hand network pipes with large RTT /spl times/ bandwidth typically become data-starved, resulting in bandwidth loss; on the other hand when multiple nodes on the clusters attempt simultaneous transfer, the network pipe could become saturated, resulting in packet loss which again may result in bandwidth degradation in large RTT /spl times/ bandwidth networks. By dynamically and automatically adjusting transfer parameters between the two clusters, such as the number of network nodes, number of socket stripes, we could achieve optimal bandwidth even when the network is under heavy contention. In order to arrive at a proper performance model for automated adjustment, we have conducted several simulations by which we have discovered that such automatic tuning would beneficial, but the ideal number of network pipes does not exactly match the simple transfer model of traditional peer-to-peer settings between single nodes.