Server connectivity error when 800 users took a test on the Moodle Mobile App

Server connectivity error when 800 users took a test on the Moodle Mobile App

by Hai Hoan To -
Number of replies: 2

Hi all,

I have a virtualization moodle site that has the following configuration:

_Web: Ram 24GB, 10 core vCPU, Disk 10k SAS, CentOS 7, Apache 2.4.6, PHP 7.4

_DB: 20GB RAM, 10 core vCPU, Disk 10k SAS, CentOS 7, 10.5.4-MariaDB

Currently, every month, the sales staff will do the test once on moodle app on tablet / mobile, the number of about 800 users. At that time, the server is slow to access, and there is a "server connection error" when you next click through a new question.

I have installed & tunning cache store (memcached, redis ....) but still access slowly. So with such traffic, what should I do next to respond.

Thank you for reading

P/S: The picture below means "server connection error"

Attachment Server Connection Error.png
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In reply to Hai Hoan To

Re: Server connectivity error when 800 users took a test on the Moodle Mobile App

by James Steerpike -
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First step would be to monitor CPU and RAM usage on your web and database server to find the bottleneck.
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In reply to Hai Hoan To

Re: Server connectivity error when 800 users took a test on the Moodle Mobile App

by Visvanath Ratnaweera -
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800 candidates taking an on-line exam at the same time is heavy. The general advice is here: https://docs.moodle.org/en/Performance_recommendations. I am not sure how far that applies to you because your users are on mobile devices. See https://moodle.org/mod/forum/view.php?id=7798.

The general approach should be still valid: You need to monitor the server closely when it gets overloaded, identify the component which hits its limits - CPU, RAM, disk I/O, network. Then treat it in a targeted way. It could mean a configuration change, could also mean adding resources.

Read the many similar discussions in this forum, https://moodle.org/mod/forum/discuss.php?d=411464 for example. And make use of the advanced search https://moodle.org/mod/forum/search.php?id=5.
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