An instructor here (actually, probably several) is rying a flipped classroom. What matters here is that there are roughly 30 students logged into WeBWorK who are all more or less asking something of the server (load a problem, assess an answer, etc) all at the same time. It slows things down to the point that this class can't really do anything, and meanwhile anyone else trying to use WeBWorK experiences the same slowdown. We regularly have about 1000 students in WW-using courses, but the load is usually so statistically spread out over the week that we haven't had this kind of slowdown (to my knowledge).
Is there a known solution for this scenario? Something in site.conf? I am going to look through all config files, but I wanted to post here in case there are known ways to deal with this well, and known potential pitfalls.
In case it is relevant, we are on Ubuntu 14.04.5 LTS. Seeing what memory options we have even during a slowdown, this is the output from `free -m`:
I had a very similar thing happen last semester when we were doing in-person quizzes with 50 students logging in at once. I followed the guide at
http://webwork.maa.org/moodle/mod/forum/discuss.php?d=3228
and made sure the server wasn't swapping to disk (added more memory to the VM) and it cleared out the issues. Have you done any of those suggestions yet?
At one point we had the same symptoms due to no low memory, but the VM was configured with one processor only. We are fine right now with 4 processors even with more than a hundred concurrent users.
Looks like half my message was clipped. I put some memory info and CPU specs for my server up. Oh well.
Wesley, thanks for pointing me to that thread. I'm trying some things there and we'll see what sticks. I don't know how to simulate the situation where the traffic gets high, so I may just have to wait until that class meets again to see.
Wesley, thanks for pointing me to that thread. I'm trying some things there and we'll see what sticks. I don't know how to simulate the situation where the traffic gets high, so I may just have to wait until that class meets again to see.