Performance tuning and capacity planning are two different animals with different goals. Tuning optimizes the existing system; capacity planning determines **what you need and when**, using current performance as a fixed baseline. The first real step in planning is to *accept* the system's present performance and estimate future need from it — not to block on hypothetical optimizations. Tuning yields diminishing returns (the rare config that doubles a cache is followed by ever-smaller wins), so planning must proceed without regard to what you might optimize; any later tweak is a bonus. Allspaw's bacon-truck: a butcher facing doubled demand can make the trucks go faster or get more trucks. Squeezing horsepower won't match the gain from simply buying more trucks — accept each truck's performance and add trucks. --- *Source: [[The Art of Capacity Planning]] (John Allspaw, O'Reilly 2008) — Ch 1 — Goals, Issues, and Processes in Capacity Planning*