Web Performance Tuning

Chapter 2. Capacity Planning

Capacity Planning Is Preemptive Performance Tuning

Since this is a book on web performance tuning, you might think a chapter on capacity planning is out of place. Not so. Capacity planning and performance tuning are in a sense the same thing: choosing system components, placement, and parameters based on performance criteria. The difference is in when they are carried out. Capacity planning is part of planning; it is generally done before any of the system has been assembled. Tuning, on the other hand, is done after the initial architecture is a fact, when you have some feedback on the performance of the architecture. Perfect capacity planning would eliminate the need for performance tuning. However, since it is impossible to predict exactly how your system will be used, you’ll find that planning can reduce the need to tune but cannot eliminate it.