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Abstract : |
Network, web, and disk I/0 traffic are usually bursty, self-similar [9, 3, 5, 6] and therefore can not be modeled adequately with Poisson arrivals[9]. However, we do want to model these types of traffic and to generate realistic traces, because of obvious applications for disk scheduling, network management, web server design. Previous models ' (like fractional BrownJan motion, FARIMA etc) tried to capture the 'burstiness'. However, the proposed models ' either require too many parameters' to fit and/or require prohibitively large (quadratic) time to generate large traces. We propose a simple, parsimonious method, the b-model, which solves both problems: It requires just one parameter, and it can easily generate large traces. In addition, it has many more attractive properties: (a) With our proposed estimation algorithm, it requires just a single pass over the actual trace to estimate b. For example, a one-day-long disk trace in milliseconds contains about 86Mb data points ' and requires about 3 minutes for model fitting and5 minutes for generation. (b) The resulting synthetic traces are very realistic: our experiments ' on real disk and web traces show that our synthetic traces match the real ones very well in terms of queuing behavior. 1, |
