It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.
Sherlock Holmes in “A Scandal in Bohemia” by Sir Arthur Conan Doyle
When faced with an underperforming and complicated system environment, the first challenge can be knowing where to begin your analysis, what data to collect, and how to analyze it. As I said in Chapter 1, performance issues can arise from anywhere, including software, hardware, and any component along the data path.
Methodologies can help the performance analyst approach complex systems by showing where to start and what steps to take to locate and analyze performance issues. For beginners, methodologies show where to ...