Managing a server is a 24/7 job. Traffic can spike, systems and applications can go offline, updates need to be installed, and RAM needs to be managed around the clock to make sure that a server – and the websites and applications hosted on it – is performing properly at all times.

Nagios server monitoring software makes server management that little bit easier. Instead of having to manually look around, a server admin can configure Nagios to automatically and periodically perform checks of various parameters of server performance.

The open source Nagios Core software has 1000s of ready-made plugins that can be installed to check system metrics, operating systems, applications and services in one single tool. And, it being automated means that the health-checks can be performed without the server admin.

Nagios can be used to monitor mission-critical server performance data like memory, disk usage, microprocessor load, and RAID arrays as well as the status of mail and web services on the server like SMTP, POP3, and HTTP. Its customisable user interface shows performance data in a visualised form, with graphs and charts that show a clear graphical representation of server performance. This all makes server management more efficient.

Contact groups

If the automated Nagios checks find anything wrong with the server’s health or performance, or even if everything is running smoothly, it sends a notification alert to a pre-defined contact group. The alert can be an SMS, email, or voice message that lets the admins know that something needs looking at – or doesn’t. These notifications come with a time stamp and a status value of 0, 1, 2 or 3 depending on the outcome of the report.

  • 0 (OK): no problem(s) found
  • 1 (WARNING): problem(s) found
  • 2 (CRITICAL): critical problem(s) found
  • 3 (UNKNOWN): server status could not be checked

Benefits of Nagios Core

As well as the huge range of functions, there are more than 1000 official plugins that can be used for checking every aspect of a server’s performance. These plugins cover most things that need checking on a server, but if there’s anything the plugins can’t do, Nagios is open source so it’s easy enough to develop a new bespoke plugin.

The software comes with various front ends and a customisable GUI, so that reports and graphs only show the relevant information to the server admin. Nagios is even compatible with climate controlled data centres, so warning notifications will be sent if a Nagios report finds that the server is too hot or too cold.

One downside of the software is that because there are so many features and plugins, it can sometimes be quite complex to configure. This can be simplified with the advanced customisation tools, and a lot of tutorials and support are available online to make the configuration easier.

Nagios & NetSaint

The software was originally called ‘NetSaint’ but when the company was challenged with a copyright dispute, they changed it to Nagios where ‘N’ represents ‘Net’ and ‘agios’ is a near transliteration of the Greek word for ‘Saint’. Close enough.

At Fasthosts, our Cloud Servers come with Nagios-based monitoring integrated into the Cloud Panel. Visit the Fasthosts website or more information on Cloud Servers.