Monitoring is one of the most important things to do when you have MariaDB in production. It helps to be proactive and avoid having performance issues. Monitoring can alert you when the usage approaches its limits, which could otherwise cause service disruption.
A lot of monitoring tools exist; some of them are closed source with a paid license, while others are free and/or open source. In this chapter, we will focus on one of the better known free solutions: Nagios. Why? In fact for the following reasons:
It's free for download and use (core version only)
It's been a popular software for a long time (more than 10 years)
It's one of the most popular monitoring tools
It's very stable for production
Plugins can be written in any language
Plugins can be easily reused on other projects (Shinken, Naemon, Sensu, and so on)
We're now going to see how to use Nagios depending on your architecture. In addition, we'll see what you can monitor and what is essential or optional.
By default...