Simulation and modeling - Old Questions

Server/System utilization is the percentage of the time that all servers are busy. System utilization factor (ρ ) is the ratio of average arrival rate (λ) to the average service rate (μ).

ρ = λ/μ in the case of a single server model

ρ = λ/μn in the case of a “n” server model

The system utilization can be increased by increasing the arrival rate which amounts to increasing the average queue length as well as the average waiting time, as shown in fig below. Under the normal circumstances 100% system utilization is not a realistic goal.