Performance FAQ

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Note: You are currently viewing documentation for Moodle 2.0. Up-to-date documentation for the latest stable version is available here: Performance FAQ.

How do you define "concurrent users"?

As has been repeatedly stressed in the Hardware and performance forum, the load on the server at a particular time depends on the number of concurrent users, not on the total number of users neither on the number of users logged-in. The term "concurrent users" is used to mean those users for whom the server is actively doing something . It may by processing a webpage written in PHP, querying the database or simply transferring a file. (see also Wikipedia Concurrency)

How do I benchmark a Moodle-site?

You can of course benchmark parts of the system separately: the hardware as seen by the operating system (eg. CPU, disk access), web server performance, database server performance, execution on PHP operations, etc. For further details see Performance_recommendations#Obtain_a_baseline_benchmark.

But there is no easy formula to deduce the maximum number of concurrent users from those results. There is a PHP-script, the Performance perspectives - a little script, circulating amoung the Moodle-community which calculates a ballpark figure. The current version is attached to posting on 25. March 2011.

Warning: Note that running this script on a production server may have unwanted side-effects. You are strongly advised to run it on a test-site.

What are PHP-accelerators?

See Wikipedia PHP accelerator.

Available software are documented under Performance_recommendations#PHP_performance.

You find some user suggestions here Update on PHP-accelerators.

How do I cluster Moodle?

See Performance_recommendations#Scalability


How do I replicate Moodle?


How to Replicate MOODLE ??!!

My site is very slow, what should I do?

First find out "how slow". (The theme-trick here).

The next question is, whether the performance is normal or something malfunctions. There are many things which can malfunction:

  • hardware
  • crashed filesystems, specially network filesystems
  • memory leaks or other crashes in the system
  • bug in Moodle
  • corrupted database
  • networking issues (DNS, firewalls, ...)

Or your performance could be "normal" under the given circumstances:

  • Are you on a dedicated server or a shared (virtual) server?
  • How much RAM, processing power do you have?
  • What is the software stack you use? (Unix or Windows, Apache or IIS, MySQL, PostgreSQL or SQL-Server, ...?)
  • how many concurrent users can you support
  • what modules/activities you use? Check Performance_recommendations#Performance of different Moodle modules

Performance_recommendations#Obtain a baseline benchmark and compare it with the published figures.

What are the requirements for N users?

A moodle setup for 10K simultaneous users

How many users will my installation support?

This is another way of asking the same question as above. Please move up.

What is the best webserver?

Should I go for 64 bit or is 32 bit OK?

What hosting provider do you recommend?

See also

Using Moodle forum discussions