Scaling for E-Business

8.6. Performance Laws

The relationships presented in this section are very simple and general, and they are known as operational results [7]. To understand the validity of these results, we do not need to resort to any complex mathematical formulation. Consider first the system of Fig. 8.11, which may be composed of a number of resources. Consider that the system was observed during T seconds and the counters registered the following measurements: i) the system was busy during B₀ seconds, ii) the number of arrivals of requests was A₀, and iii) the number of completed requests was C₀. From these simple measurement data, we can derive a series of other measurements, such as arrival rate, completion rate, utilization, and mean service time. The ...