Persistence and Communication State Transfer in an Asynchronous Pipe Mechanism

Abstract

Wide-area distributed systems offer new opportunities for executing large-scale scientific applications. On these systems, communication mechanisms have to deal with dynamic resource availability and the potential for resource and network failures. Connectivity losses can affect the execution of workflow applications, which require reliable data transport between components. We present the design and implementation of p-channels, an asynchronous and fault-tolerant pipe mechanism suitable for coupling workflow components. Fault-tolerant communication is made possible by persistence, through adaptive caching of pipe segments while providing direct data streaming. We present the distributed algorithm for implementing: (a) caching of pipe data segments; (b) asynchronous read operation; and (c) communication state transfer to handle dynamic process joins and leaves.