Soraya Zertal

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A workload analysis technique is presented that processes data from operation type traces and creates a Hidden Markov Model (HMM) to represent the workload that generated those traces. The HMM can be used to create representative traces for performance models, such as simulators, avoiding the need to repeatedly acquire suitable traces. It can also be used(More)
Flash memory is becoming an increasingly important storage component among non-volatile storage devices. Its cost is decreasing dramatically, which makes it a serious competitor of disks and a candidate for enterprise-tier storage device of the future. Consequently, there is an urgent need for models and tools to analyse its behaviour and evaluate its(More)
Useful analytical models of storage system performance must support the characteristics exhibited by real I/O workloads. Two essential features are the ability to cater for bursty arrival streams and to support a given distribution of I/O request size. This paper develops and applies the theory of bulk arrivals in queueing networks to support these(More)
A recent queueing-based modelling methodology of RAID systems compared the mean disk access times of the two most common variants, RAID0-1 and RAID5, as well as a multi-RAID system in which they coexist. Accesses to multiple disks occur concurrently for each logical (user) request and complete only when every disk involved has completed. The models(More)