9.1 OVERVIEW

The performance of a UNIX system is best defined as the ability of the system to accomplish a given task or set of tasks. Good performance is a slippery target that depends on a great many variables, including user perception, performance indexes, and available system resources. A system administrator is frequently called upon to evaluate and improve the performance of a system; the ability to do so to the satisfaction of the user community can be a challenging task. In this chapter, I will discuss the performance indexes available to you in quantifying system performance, define the four primary system resource categories that effect UNIX system performance and the tools to measure the performance indexes of these categories, and provide strategies for translating user complaints into basic and objective information useful for evaluating performance problems.

Once the performance of a system has been quantified and performance problems have been identified, the next step is tuning. Tuning is the process of adjusting the system configuration to compensate for an identified performance bottleneck. Following the discussion of performance indexes and system monitoring, I will outline a tuning methodology that aims for the best average performance over time.

9.2 PERFORMANCE MANAGEMENT

Performance management is an ongoing process of continued system monitoring and configuration adjustments to maintain an acceptable level of performance. In order to successfully manage performance, a system administrator must understand:

9.3 PERFORMANCE INDEXES

There are a variety of...