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Rice University Department of Computer Science presents AJAY GULATI Master of Science Thesis Defense Scheduling with QoS in Parallel I/O Systems Abstract Parallel I/O architectures have become attractive in context of high performance computing and services provided by high bandwidth data centers. It is challenging to provide a scheduling technique that can provide QoS guarantees and is highly efficient. In this thesis we first introduce the problem of maximizing the throughput for a parallel I/O system that is simultaneously accessed by several concurrent applications. We show that the problem of obtaining a minimum length schedule is NP-\emph{complete}. In addition to being intractable and requiring full knowledge about future requests, the optimal schedule may not be desirable from the point of view of fairness. We present fairness metrics for parallel I/O and provide fair scheduling schemes for some represent ative situations. In particular we study schemes that support fairness at every I/O step (local fairness) and during a certain window of time(global fairness). We also present a more general algorithm for weighted allocation of disk system bandwidth to multiple reference strings. All the three algorithms run in polynomial time, O((n+D)nD) and are work conserving. Tuesday, July 20, 2004 at 11:00 a.m. in DH 1049 Copyright 2000 Rice University site problems: www@cs.rice.edu --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---