Performance FAQ

How do you define "concurrent users"?

As has been repeatedly stressed in the Hardware and performance forum, the load on the server depends primarily on the number of concurrent users, not on the total number of users neither the number of users logged-in at a given time. In this context, the concurrent users are those for whom the server actively doing something (see Wikipedia Concurrency). It may by processing a webpage written in PHP, querying the database or simply transferring a file.

How do I benchmark a Moodle-site?

You can of course benchmark each component of the software stack: operating system, webserver, database server, PHP (see Performance#Obtain_a_baseline_benchmark). But there is no easy formula to deduct 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 the posting on 1. March 2007.

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

What are PHP-accelerators?

See Wikipedia article PHP accelerator.

Available software are documented Performance#PHP_performance.

How do I cluster Moodle?

See Performance#Scalability

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

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

• Is it a root-server, dedicated server, virtual (shared) 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 slows the system down
• what modules/activities they use? Check Performance#Performance of different Moodle modules
• is your networt setup property? DNS, firewalls. Also check local firewalls and other local security tools?

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

See also:

• 1000 concurrent users
• Tool to estimate server's maximum concurrent users

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 hosting provider do you recommend?

http://moodle.org/mod/forum/discuss.php?d=99405

See also

Moodle Docs

• Performance

Forum discussions

• Handling Moodle database load - a solution!