This page is extremely rough. It’s just my rough notes with very little editing or checking. Be warned!
If you’re just developing on your laptop/desktop, run Devstack. it is a lot easier to develop on than the full production server and “only” uses 2GB of RAM.
The stock edX Ubuntu deployment is set up to give you good performance, but it assumes that you have a lot of hardware available.
The recommended config for the edX Ubuntu deployment recommends an Amazon instance with 4GB of RAM. There are two problems with this:
If you’re running a big edX instance (tens of thousands of students), then yeah, you probably need some bigger hardware and a lot of RAM. If you’re just doing a closed course, 4GB instances are vast overkill.
You can reduce the memory usage to something sane by:
Reduce the number of workers for a bunch of services (lms, cms, xqueue). By default, lms uses 8, and each uses ~80MB of RAM (so 640MB just for the LMS). I use 3 both in dev and production.
Restart the LMS with
/edx/bin/supervisorctl restart edxapp:lms
Restart the CMS with
/edx/bin/supervisorctl restart edxapp:cms
Restart xqueue with
/edx/bin/supervisorctl restart xqueue
Restart ora with
/edx/bin/supervisorctl restart ora
Restart ora_celery with
/edx/bin/supervisorctl restart ora_celery
Restarting through supervisor doesn’t seem to change the number of workers; as a stop-gap solution, just reboot the machine (yuck!)
You could also turn off some services, like the grader, forums or java
You could also use zram
Try KSM. Only for KVM VMs right now, but there are some attempts to make it work for all processes, which would be excellent with LXC: https://plus.google.com/+MaksimMelnikau/posts/QfhAchyzYva http://vleu.net/ksm_preload/ http://kerneldedup.org/en http://kerneldedup.org/en/projects/uksm/introduction/ https://github.com/prashmohan/lxc-fork/blob/master/Documentation/vm/ksm.txt