A scalable MPI implementation of an ad-hoc parallel I/O system

This paper presents the novel design, implementation and evaluation of an ad-hoc parallel I/O system (AHPIOS). AHPIOS is the first scalable parallel I/O system completely implemented in Message Passing Interface (MPI). The MPI implementation brings the advantages of portability, scalability and high-performance. AHPIOS allows MPI applications to dynamically manage and scale distributed partitions in a convenient way. The configuration of both MPI-IO and storage management system is unified and allows for a tight integration of the optimizations of these layers. AHPIOS partitions are elastic: they conveniently scale up and down with the number of resources. We develop two collective I/O strategies, which leverage a two-tiered cooperative cache in order to exploit the spatial locality of data-intensive parallel applications. The file access latency is hidden from the applications through an asynchronous data staging strategy. The two-tiered cooperative cache scales with both number of processors and storage resources. Our experimental section demonstrates that with various optimizations integrated AHPIOS offers a substantial performance benefit over the traditional MPI-IO solutions on both PVFS or Lustre parallel file systems. Index Terms Parallel I/O, Parallel Systems, Distributed File Systems, Parallelism and Concurrency.