Our organization plans for a Moodle upgrade from Moodle 3.2.2+ to Moodle 3.5.2+. Part of this project involves a server upgrade from Ubuntu 14.04.5 LTS to Ubuntu 18.04.1 LTS.
We built Ubuntu 18.04.1 LTS, then copied the current Moodle 3.2.2+ site. It worked fine as a test site, we did all sorts of tests then decided to make it live. Unfortunately the site crashed frequently, the server froze, we could not ssh to it. From VMWARE logs:
Message: The CPU has been disabled by the guest operating system. Power off or reset the virtual machine.
We have no idea why the power off was done by the guest operating system. Will that be a Moodle problem? We thought it might be too many students logging and submitting which caused the problem. We put Moodle into maintenance mode, but the server still froze after several hours.
The server never freeze again after we switched it back to test site.
Did anybody have similar problem? We are totally lost in this situation. Hope somebody could help.
Thanks a lot!