15.1 General Tuning Guidelines

The outcome of the tuning suggestions provided in this chapter might vary depending on your specific environment. When deciding the tuning parameters that are suitable for your needs, keep the following guidelines in mind:

• Adjust one parameter at a time

  To the extent possible, make one adjustment at a time. Measure the performance before and after each change, and revert any change that does not result in measurable improvement.

• Establish test cases that you can use to create a performance benchmark

  Before changing any parameter, set up test cases, and automate them if possible, to test the effect of the changes on performance.

• Tune gradually

  When adjusting a quantitative parameter, make changes in small increments. This approach is most likely to help you identify the optimal setting quickly.

• Start afresh after a hardware or software change

  At each major system change, a hardware or software upgrade, for example, verify whether the previous tuning changes still apply.