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I'm doing a report and needed to have a test for the scalability of a mind map database software design idea. I wanted to use the USL equation to get a quantifiable metric for scalability, but I have no idea what range is considered good for USL. Any help would be appreciated :)

USL Eq'n: C(N) = N/ (1 + α (N − 1) + β N (N − 1))

The three terms in the denominator of eqn. are associated repectively with the three Cs: the level of concurrency, a contention penalty (with stength α) and a coherency penalty (with stength β). The parameter values are defined in the range: 0 ≤ α, β < 1. The independent variable N can represent either

tshepang
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user3476885
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Do you mean number of measurements by "What range"? If yes then you cannot be assured about the required number of measured data points beforehand. Until you don't see any change in the predicted maximum number of concurrency after including more data points you have to keep adding more data points.

The estimated parameters and predictions there of are not reliable if you use the MS Excel spread sheet method explained in the book "Guerrilla Capacity Planning" book. Check out the paper "Mythbuster for the Guerrillas" to understand why and how to get reliable results. It might be worth to read the paper "Better Prediction Using the Super-serial Scalability Law Explained by the Least Square Error Principle and the Machine Repairman Model”.

Jayanta Choudhury
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