Question

Adding more memory to linux server

Posted June 30, 2014 8.1k views

Recently I’ve had mysql crash on my wordpress site multiple times, giving me the “error establishing connection to database” error.

I have a 1gb droplet and I think the problem might be low memory on my linux server. How can I fix this problem so that I don’t run out of memory?

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2 answers

Try adding swap to your droplet: How To Add Swap on Ubuntu 12.04.

If that doesn’t fix it, you might want to consider upgrading your droplet as it’s running out of memory or switching from Apache to nginx.

by Etel Sverdlov
Linux swaps allow a system to harness more memory than was originally physically available. Here's how to set up a linux swap file on Ubuntu 12.04
  • Hey Kamal,

    If I were to upgrade my droplet (I’m already at 1gb), would that definitely fix the problem? I don’t particularly care about paying more but I just can’t imagine that my relatively simple wordpress site (with a small database of maybe 4000 datapoints) could be that memory-intensive.

  • Running out of memory is most likely why MySQL is crashing, so adding more RAM to your droplet should fix the problem. You can make sure that’s the case by checking MySQL’s error log for details on why it’s crashing:

    sudo tail -40 /var/log/mysql.err
    

Hello, all

I will recommend you to check our article on How To Debug the WordPress Error Establishing Database Connection:

https://www.digitalocean.com/community/tutorials/how-to-debug-the-wordpress-error-establishing-database-connection

This crash is most likely due to your system running out of memory. I’d suggest that you add a swap file to give yourself a bit more of a buffer. Check out this tutorial:

How To Add Swap on Ubuntu

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

by Brian Boucheron
WordPress is one of the most popular open source content management systems in the world. Although it started out focused on blogging, over the years it has developed into a more flexible platform for websites in general. After almost fifteen years of development it is quite polished and robust, yet issues can still come up. If you've recently attempted to load your WordPress-powered website and instead saw a message stating "Error Establishing Database Connection", the cause is most often...