What is most valuable?
The first most valuable feature are the notifications that can be customized and even received via WhatsApp.
Another valuable feature is the reporting. As far as I know, there's no way to cheat on the reporting, that is, there's no way to go into the system to change the results. This makes the reporting feature very reliable. The reports are also very easy to understand, which is good when I present them to my boss.
Lastly, Nagios is not a resource hog. I can set it up on a busy server and it will still function reliably. This allows sysadmins to keep server maintenance costs low.
How has it helped my organization?
I can give an example. It was during a seasonal festival and visitors to our e-commerce site increase several-fold. The log partition quickly filled up within two days. If it wasn't for Nagios' alerts every minute until we acknowledged the problem, our website would have stopped working. (I can't remember why the logrotate didn't work, though.)
What needs improvement?
I like to have the option to configure Nagios using the web interface. Although I agree that the CLI gives a lot of customization options, I'd like to take a break from looking at lines of words. Also, configuration via a web interface could be expanded to not-so-Linux-literate users.
What was my experience with deployment of the solution?
There have been no issues with the deployment.
What do I think about the stability of the solution?
I did encounter stability issues when exploring plugins, but not with Nagios itself. Other than that, I never faced any issues on the production side.
What do I think about the scalability of the solution?
There have been no issues scaling it for our needs.
How are customer service and technical support?
Since Nagios is open source, I had to rely completely on forums and web articles. However, Nagios was set up before I joined the company, so my colleagues were able to give me ample support when trying to understand how it works.
Which solution did I use previously and why did I switch?
I never used a different solution because this current position is my first. Nagios was already set up before I joined the company. Nagios was already good enough for us so we didn't allocate time to research other products.
How was the initial setup?
The initial setup is easy if you just follow the basic guide. The complexity comes when you want to customize it to suit your environment. For example, different plugins require different configurations. There's also another challenge in that Nagios was originally designed to monitor Linux servers but has since expanded to Windows servers as well.
What about the implementation team?
It was all done by us. We were given time to do our own research and through regular testing, trials and errors, we finally implemented it. My advice is to not be scared by the need to configure everything through the CLI. It's actually quite fun and rewarding when you see your monitoring system finally up and you know you can count on it to give you a heads up on alerts before something nasty happens to your server.
What was our ROI?
Nagios is able to minimize server downtime and this in turn helps to generate more revenue.
What's my experience with pricing, setup cost, and licensing?
Nagios is open sourced, therefore there's no need for licensing.
What other advice do I have?
The product is robust and reliable. The notifications can be customized so that I can even configure it to send the notifications via WhatsApp! Last but not least, the reporting feature is very easy to understand, which is good when presenting to my boss.