Model-Based EIS Performability Analysis

In this paper we propose a methodology for the modelling, verification and performance evaluation of communication components of software for enterprise information systems. The methodology is centered upon model-driven development using a subset of UML 2.0 diagrams. It is supported by the proSPEX model processing tool which offers a simulation-based executable verification environment. The model-based development of communication components of wireless middleware solutions is discussed as a motivational example

Using UML Models for the Performance Analysis of Network Systems

The automated functional and performance analysis of communication systems specified with some Formal Description Technique has long been the goal of telecommunication engineers. In the past SDL and Petri nets have been the most popular FDTs for the purpose. With the growth in popularity of UML the most obvious question to ask is whether one can translate one or more UML diagrams describing a system to a performance model. Until the advent of UML 2.0, that has been an impossible task since the semantics were not clear. Even though the UML semantics is still not clear for the purpose, with UML 2.0 now released and using ITU recommendation Z.109, we describe in this paper a methodology and tool called proSPEX, for the design and performance analysis of communication protocols specified with UML

A Storage System Workload Analyzer

The analysis of storage system workloads is important for a number of reasons. It is necessary to understand the usage patterns of secondary storage to enable architects to understand and build a new, or improve upon an existing storage system. It is also important for a storage administrator to understand the workload profile when configuring and tuning a system. Furthermore, the analysis of workloads is necessary to understand the storage requirements and behavior of application software. A different reason for workload analysis, is the need to come up with adequate models for performance evaluation. For the evaluation, based on simulation or otherwise, to be reliable one has to analyze, understand and adequately model the workloads. In this paper we describe a methodology to go about storage system workload analysis and illustrate it with a general tool we call the Enterprize Storage System Workload Analyzer or ESSWA. Although such analyzes are not new, we believe our proposals have a number of advantages over previous analyzers described in the literature. We experimented with ESSWA by analyzing workloads represented by three sets of publicly available workload traces

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Analyzing Storage System Workloads

Disk storage subsystems have not kept up the speed with processors. Processor performance has been increasing at a much higher rate than that of disk drives. Therefore, I/O subsystem has become a bottleneck in current computer systems. With this in mind the research community is looking into ways of improving the I/O subsystem. IBM and HP are among the organizations doing research and development of high performance storage systems also referred to as Enterprise Storage Systems (ESSs). Much of this effort goes into the evaluation of these systems for correctness and performance. For these evaluations, using simulations or otherwise, to be reliable, there is need to correctly understand and model the disk I/O workloads also known as I/O traffic or physical I/O workloads. Therefore in our work, we analyzed I/O workload traces to derive statistics which can be used as a guide in the (a) modelling of I/O workload and subsequent production of I/O workload representative of the actual I/O workload for evaluation and (b) optimization of the storage systems. Our results show that the distribution of inter-arrival times of I/O requests are heavy-tailed, and that the I/O request sizes are a function of the operating system