speed up moodle, Apache performance with PHP memory limit, PHP accelerator, TMPFS filesystem

1. PHP performance is better when installed as an Apache module (rather than a CGI) in Fedora/Linux.

2. Check the memory_limit in php.ini,
For Moodle 1.7 or later, the value of memory_limit should be > 40M.

3. Use a PHP accelerator to ease CPU load, such as PHPA, Xcache or eAccelerator.

4. Read/Write performance can be improved by putting the cached PHP pages on a TMPFS filesystem.
Note: The cache contents will vanished when there is a power failure or if the server reboots.