9.1. Not Always a Silver Bullet
This chapter assumes that it is possible to solve a performance problem by changing software. Tuning an application or system to achieve a target performance goal is not always possible. If tuning fails, it may require a hardware upgrade or change. If the capacity of the system is maxed out, performance tuning only helps to a certain extent.
For example, it may be necessary (or even cheaper) to just upgrade the amount of system memory rather than track down which applications are using system memory, and then tune them so that they reduce their usage. The decision to just upgrade the system hardware rather than track down and tune a particular performance problem depends on the problem and is a value judgment of the individual investigating it. It really depends on which option is cheaper, either time-wise (to investigate the problem) or money-wise (to buy new hardware). Ultimately, in some situations, tuning will be the preferred or only option, so that is what this chapter describes.