I just wanted to share my experience setting up tutor with limited resources, in case someone else finds it helpful. I am experimenting with an online course on a VPS debian with 30G hard drive space and only 2 CPU and 4G RAM.
Initially, RAM would fill up completely and debian would activate the kswapd daemon which would block the system completely. Connections would time out and I would be forced to restart tutor. I had already set the uswgi worker processes to one for CMS and LMS.
In the end, I just set up some swap on the hard drive and the system has since run smoothly. I know swap partitions are usually discouraged on solid state drives, but I did a bit of reading and reached the conclusion that it was not such a big deal.