Why not MRTG , rrdtool, <insert favourite tool here>?

MRTG is a fine tool and I recommend it wholeheartedly. In the past I have implemented basic monitoring on a number of systems using MRTG. People are generally satisfied with the data and it takes very little effort to setup and manage.

I haven’t directly setup rrdtool but have it running under hobbit (a highly recommended operations management tool) and am very happy with the results of both. Rrdtool expands on the idea of MRTG by adding more data, better graphing, and better performance.

Why aren’t I happy with these tools? For my purposes both are based on some assumptions about data use that I don’t like for some situations:

• All data that I collect is immediately interesting so you’d better graph it. In practice I would rather collect a whole bunch of related stuff, graph the important bits and hold onto the rest for possible future studies.
• To save space, older data is averaged and summarised for longer term graphs. For me graphs are nice but they aren’t the whole story – I may want to create other graphs or ad-hoc reports on my data later one that I hadn’t thought of so don’t want my data summarised away. Indiscriminate smoothing of older data can also destroy important details of peak non-reschedulable workload that is important for decent capacity planning.
• Dedicated database format. How do I access that data to do ad-hoc queries using excel? A quick and dirty java program? Set up a simple query using php? By using one of the common free databases I can immediately leverage off thousands of other people’s work in interfacing to other environments.

Having said that, both are much easier to set up and manage than the FreePDB suite of programs. If all you need are some nice graphs to keep everyone happy and don’t have time to invest in managing a full Performance Database then you should give them a try.