Question

Wordpress site error 504 and out of memory error and 100% cpu spike

Posted June 9, 2020 535 views
NginxMySQLWordPressUbuntu 20.04

Ive recently migrated my wordpress site to a new ubuntu 20.04 droplet. Im using nginx + mysql and using cloudflare as a cdn. I keep getting 504 errors from cloudflare and when i log in to the console there is a string of out of memory errors for mysql. The Digital ocean dashboard shows 100% cpu usage but after waiting for a few minutes or rebooting the server the issue stops. Is there a way for me to check what is using up all the memory / cpu ? This seems to happen mainly when i login and change something in wp-admin like updating a post, page or a product but that’s not always the case.
Any help would be greatly appreciated.

My site is www.themusicvault.co.uk

1 comment
  • If you didn’t make any changes to your Cloudflare settings before this started happening, it must be something on the origin server that is causing this. You should check there for error logs.

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2 answers

Happened again this morning and i had to reboot the server via console. Here are some screenshots of the graph on the digital ocean dashboard
https://drive.google.com/drive/folders/1t-FFv8akb37wrbvykDI3f4tuy-OB4qL_?usp=sharing

Hello, all

You will most definitely need to upgrade your droplet as you’re running out of memory and your application/website needs more resources in order to continue to operate.

What you can also do is to use the MySQLTuner script.

The MySQLTuner is a script written in Perl and allows you to quickly test your MySQL configuration and it gives you suggestions for adjustments to increase performance and stability.

According to the official GitHub page, it supports 300 indicators for MySQL/MariaDB/Percona Server in this last version.

To run the script you could do the following:

  • SSH to your Droplet
  • Download the script:
wget http://mysqltuner.pl/ -O mysqltuner.pl
  • Then execute it:
perl mysqltuner.pl

The script would run multiple checks against your MySQL instance, all checks done by MySQLTuner are documented here.

Also as stated in the official documentation, it is still extremely important for you to fully understand each change you make to a MySQL database server. If you don’t understand portions of the script’s output, or if you don’t understand the recommendations, you should consult a knowledgeable DBA or system administrator that you trust.

As a good practice make sure to always test your changes on staging environments before implementing them on your production database.

On the same note, if you want to have a worry-free MySQL hosting and focus on your application, I would recommend trying out the DigitalOcean Managed Databases:

https://www.digitalocean.com/products/managed-databases-mysql/

This was mini tutorial was posted from bobbyiliev in this question in our community: https://www.digitalocean.com/community/questions/how-to-tweak-mysql-mariadb-configuration-for-increased-performance-and-stability

You can also create a simple bash script to check if MySQL is running and if not to restart it.

#!/bin/bash

# Check if MySQL is running
sudo service mysql status > /dev/null 2>&1

# Restart the MySQL service if it's not running.
if [ $? != 0 ]; then
    sudo service mysql restart
fi

Run this script every 5 minutes using a cron job like this one:

 */5 * * * * /home/user/scripts/monitor.sh > /dev/null 2>&1

Hope that this helps!
Regards,
Alex