On the Ibuildings blog, Ian Barber has a reminder to PHP developers out there used to their servers "just working" because of the popularity of LAMP. He recommends digging a little deeper to the "behind the scenes" of how the server is configured.
PHP programmers generally know what a good systems architecture should look like, but it is often a reality of development that they will have little input on the system itself until the last minute. In fact, it's far from uncommon for a developer to be faced with an off-the-shelf dedicated LAMP server, and left up to their own devices.
He recommends getting to know things like the package manager for your distribution (apt, yum, yast, etc), stripping down the modules your installation is using, check that all of the packages in use need to be enabled and ensure that the network connection is set up correctly and is what you need for the site.