Visvanath Ratnaweera

In line with Emilio, see Moodle quiz performance testing:

- Your CPU (#processors/#cores) will control the maximum number of simultaneous (exam starting at XX:XX hours) quiz candidates. A 4 core (vCPUs) quality Linux VM can handle 200 such candidates. If you don't have seasoned system administrators, then double that.

 

- The RAM will not affect the peak but needed for good steady response. You achieve that by loading the whole database in to RAM. So add that much to the RAM needed by everything else: the OS, web server, PHP (either as part of the web server or separate as php-fpm), DBMS, cache server (Redis). A calculation is not possible without specific numbers and sizes of each and not reliable since your database will grow. For a very rough initial value, say 1 GB database buffer, 2 GB for the system, 1 GB for the DBMS, are still 4 GB. If you go by the common formula "RAM in GB = 2-4 times vCPUs", means 8-16 GB, you'll have plenty of elbow space (for the web server, php-fpm if it is the case, and cache server).

 

- Yes, SSD storage gives a big boost. Nowadays you get only SSD in VMs. I don't know how much a minimal Debian server will take, sure less than 5 GB. Then you'll have the remaining storage for uploaded data, system log files, etc. and the (growing) database.

 

In summary, 

- 4-8 vCPU depending on your Linux expertise (and the quality of the VM)

- 8-32 GB RAM depending on the side of the database, safety margin you need (and the size of your wallet)

- 50-200 GB depending on your future growth (ambitions)

I too can't believe MDL-41924 from 2013(!) is still relevant. But the ticket has not been closed. And still there are reports of exploding question categories (including mine).

 

And about MDL-61267, it may or may not be related. In the German forum recently somebody cleaned a 3 million question collections by simply purging the "random" type questions. Out of my 2.5 million only 12'000 were of that type and gone - which is unnoticeable.

 

I hope a developer who knows it all from inside will come to the rescue.

Only now I saw your comments in MDL-41924. The connection is right at the beginning: "Is the tricky part of this problem just random questions? If it is, and if we are trying to design a solution that would backup all possible random questions anywhere, then indeed I find it very difficult to imagine a fix." The idea of random questions doesn't have a clean solution (in the design) without going in to ugly workarounds, like duplicating all the question categories. That is why that ticket is open and actively discussed since 2013!

 

Also worth re-iterating How_to_minimize_the_question_bank_when_doing_backup/restore - since /27/.

Die Dinge wie php_safemode und open_basedir sind nicht kompatibel mit Moodle. Beim Hoster melden!

Wie hast du Moodle ueberhaupt installiert? Ist es ein Shared-hosting mit einem Tool Softaculous im Panel integriert? Softaculous ist grobfahrlaessig, das weiss ich von engl. Moodle-Foren. Wenn Softaculous im Spiel ist, weiss ich nichts!

Mit Debugging die Details holen und hier posten!