Cleanup
Location: Administration > Server > Cleanup
Unsubscribe users from courses after
To help keep lists of participants up-to-date, you can tell Moodle to unenrol any student who hasn't logged in for a certain amount of time. Be sure to keep this time long enough so students aren't unenrolled accidentally while they still need access to the course.
Delete unconfirmed users after
If you're using Email-based self-registration users must confirm their account within a certain time-frame. Once the time set here has passed, any account that hasn't been confirmed will be deleted. 7 days is a good setting.
Keep logs for
Moodle keeps extensive logs of user activity. Eventually, however, the logs will become so large that they begin to clog your server. Limiting the length of time logs are kept for will reduce database table size. Generally, a year is enough time to keep logs for.
See also
- Using Moodle How do I prune mdl_log table? forum discussion