Visvanath Ratnaweera

There is a limit to the load any server can handle. As Howard already pointed out 2000 users taking an exam at the same time create a huge load.

To investigate whether that limit can be raised you need to provide the information as requested in Before you post.. read this... You can start the journey on your own as explained in the documents Performance and Performance FAQ.

P.S. It is unlikely that the cause of eric's problem is the same as yours. So yours should be a new discussion. In fact, there is a dedicated forum dedicated to this topic, the Hardware and performance forum. You don't have to repost. The moderator may move your sub-discussion to that forum.

A second opinion on Ken's opinion? Ha, ha, ha! It is like asking the general practitioner to endorse the specialist's opinion. But this particular question is an easy one: Git is the best, it is the work of Linus Torvalds - next to Linux, where we meet.

Seriously, I'm surprised that "an install where so many things are tried out" is not on Git.

About the other problem you had with a Moodle 3 upgrade, the rational way is to investigate what went (you did) wrong and learn from it, not to avoid double jumps. One could argue that the missing Git caused it. Either way, I am cautious, it looks like you work straight on the production Moodle, not on a trial instance. Again, may be, because you miss the correct tool?
'-)

In that case I would have gone to 4.3. It has corrected some overdone UX changes in Moodle 4 and after four minor releases very stable. Your bad experience with the long jump 4.1 LTS > 4.4 doesn't mean that long jumps generally go bad.

Moodle 4.1 LTS is PHP 8.0 capable and even PHP 8.1 capable since Moodle 4.1.2. See http://www.syndrega.ch/blog/#php-and-dbms-compatibility-of-major-moodle-releases. So one alternative would be to upgrade PHP to 8.0 or 8.1 first.

Caution: I don't know whether it is a good idea to upgrade PHP in a production server.

And also, I don't know why you go from 4.1 LTS to 4.2, which as a non-LTS has a shorter life span. See https://moodledev.io/general/releases.