noticed that processattempt.php?cmid=25 take more than 30s
you mean process count?
I can't exactly remember but this was happened when only one user accessing moodle.
Uptime: 1759 Threads: 13 Questions: 6776 Slow queries: 0 Opens: 87 Flush tables: 1 Open tables: 81 Queries per second avg: 3.85
Please note that I could not collect my details when the incident happened (at that time system was booted using USB drive instead of local disk).
Above stats from same moodle system but on a VM with 1.5GB RAM and Single core CPU and only single user on moodle.
I am planning to reproduce the same issue within next few days.
It would be great if you can mention what stats may specially required in terms of moodle issues.
DB: Mariadb 10.2
Btw, why disk InnoDB disk writes instead of reads during a exam where user just moving one question to another without selecting an answer?
Is that due to moodle keep writing current working page/question?
This server suppose to serve users 20-50 at a time.
I highly appreciate if you can mention any recommended configuration available.
"Please note that I could not collect my details when the incident happened (at that time system was booted using USB drive instead of local disk)."
Is it just me that thinks that might have been the problem...
The point is to look at every bit of information you can find while reproducing the incident and see if anything jumps out. It's not very scientific - but that's the place to start.