Log analysis is a fairly common task in the field of web development, most often analysis of web server traffic logs or what Wikipedia refers to as web analytics. PHP has no officially supported extensions designed specifically for log analysis. There are no related extensions in PECL. The only remotely related extension in PEAR is PEAR_Log, which for generating logs rather than parsing or analyzing them. In short, there is no common solution here.

He looks at the options that developers do have - make their own solution or go with a third party option. He believes, though, that a PECL extension would be more the way to go, integrating with PHP more closely and allow for easier parsing and manipulating of the data in their own log files.

They seperate it out into three different sections - setting out your performance goals, analysing your site for current traffic/resource consumption, and the actual implementation of the performance settings. They give a few steps here to follow to check what your server is currently using and some links to other tips on tuning the various pieces of the puzzle.

One thing that they mention that's worth repeating to any and all web developers out there: "Apache is bandwidth limited, PHP is CPU limited, and MySQL is memory limited and disk I/O bound".