Performance by Design: Computer Capacity Planning by Example

Chapter 12. Single Class MVA

Introduction

The Achilles’ heel of Markov models is their susceptibility to state space explosion. Even in simple models, where there are a fixed number of customers, where all customers are identical, and where the demands placed by each customer on each device are exponentially distributed, the number of states is given by the expression

where N is the number of customers and K is the number of devices. For small systems, such as the database server example in the previous chapter with N = 2 and K = 3, the number of states is 6. However, in a moderate sized office network with, say, 25 users and 25 workstations, the ...