Understanding the LAMP architecture

Applications using the LAMP (Linux, Apache, MySQL, PHP/Perl) architecture are constantly being developed and deployed. But often the server administrator has little control over the application itself because it's written by someone else. This series of three articles discusses many of the server configuration items that can make or break an application's performance. This first article covers the LAMP architecture, some measurement techniques, and some basic system tweaks. Successive articles investigate tuning the Apache, MySQL, and PHP components.

Linux, Apache, MySQL, and PHP (or Perl) are the foundation of many Web applications, from to-do lists to blogs to e-commerce sites. WordPress and Pligg are but two common software packages powering high-volume Web sites. This architecture has come to be known simply as LAMP. Almost every distribution of Linux includes Apache, MySQL, PHP, and Perl, so installing the LAMP software is almost as easy as saying it.

This ease of installation gives the impression that the software runs itself, which is simply not true. Eventually the load on the application outgrows the settings that come bundled with the back-end servers and application performance suffers. LAMP installations require constant monitoring, tuning, and evaluation.

Tuning a system has different meanings to different people. This series of articles focuses on tuning the LAMP components -- Linux, Apache, MySQL, and PHP. Tuning the application itself is yet another complex matter. There is a symbiotic relationship between the application and the back-end servers: a poorly tuned server causes even the best application to fail under load, and there's only so much tuning one can do to a server before a badly written application slows to a crawl. Fortunately, proper system tuning and monitoring can point to problems in the application.