My old server, 2x4 Xeon, 8GB memory, crashed with 80 students taking a gateway quiz.
I installed Webwork 2.15 live DVD on a newer server, 2x4 Xeon, 32GB memory, Ubuntu 18, by default:
It crashed with 56 students taking the same gateway quiz.
1- What do you recommend I change parameters to?
2- If I have a set of 40 students taking the test say from 9 to 10 am, next set taking quiz from 10 to 11 am, should I tell the first set to logoff? of just leave the server alone to log them off at idle time?
3- How long is the idle time during a gateway quiz before the system logs you off?
With 32GB of RAM you can probably leave MaxRequestWorkers at 150, but if you continue to run into trouble that would be the value to lower.
In terms of students logging off, that should make no difference to WW performance. The server is only working when a page is loaded, so a student having an active session shouldn't have any effect.
The idle time before a student is logged out is controlled by the variable $sessionKeyTimeout, which defaults to 30 minutes. You can increase that by overriding this variable in localOverrides.conf. Just note that it is measured in seconds, so to set the timeout to 60 minutes you would use
$sessionKeyTimeout = 60*60;
It's worth noting that the timeout resets every time a page is loaded, so if a student clicks "preview answers" it will refresh their session. It's also worth encouraging the students to preview often when working on a gateway quiz because this saves their answers to the database, which means they can be restored if the student has computer problems, and also can be accessed if a student doesn't submit in time.
Thank you so much for the information. I can remind my students, but at the end of the day, there will be a good number that became engrossed doing the quizz and forget to click GRADE. I think having the system automatically GRADE when the clock reaches ZERO is an improvement/mod worth considering.