Performance recommendations

Large installations tend to separate the web server and database onto separate servers, although for smaller installations this is typically not necessary.

The consensus in the Moodle community seems to be that a Linux-based webserver running Apache, with PHP installed as well as a PHP accelerator, is commonly the best choice.

It is possible to load-balance a Moodle installation, for example by using more than one webserver. The separate webservers should query the same database and refer to the same filestore area, but otherwise the separation of the application layers is complete enough to make this kind of clustering feasible. Similarly, the database could be a cluster of servers (e.g. a MySQL cluster).

See also moodle.org's Servers and Performance discussion area.

Web server performance

• The amount of RAM on your web server is the strongest factor in performance - get as much as possible (eg 4GB).
• Linux or Unix is the recommended operating system for the server. They perform much better than Mac OSX or Windows servers at high loads.
• You are strongly recommended to use a PHP accelerator to ease CPU load, such as Turck MMCache or PHPA.
• Note that using secure web connections (https rather than http) carries a higher processing burden, both for the webserver and the client - particularly because cacheing cannot be used as effectively, so the number of file requests is likely to increase dramatically. For this reason using https for all Moodle pages is not recommended. You can enable https just for the login screen, simply from Moodle's config page.

Database performance

• Arguments in favour of PostgreSQL
• Increasing the database connection lifetime

Performance of different Moodle modules

Moodle's activity modules, filters, and other plugins can be activated/deactivated.

• The Chat module is said to be a hog in terms of frequent HTTP requests to the main server. This can be improved if you're using a Unix-based webserver by running the chat in daemon mode.
• Brief report on performance for 55 students simultaneously using Quiz