rrd tool constellation plot and x axis plot

Question

1) Is it possible to draw constellation plot in rrd tool ? i.e. plotting the values as dot instead of line connecting all data points.

2) Is it possible to store and plot normal integer in x axis of rrdtool graph instead of time?

Thanks in advance.

Answer 1

The short answer is no. This is because of the way that RRDTool works; it is optimised to work well with one sort of data, but is not as generic as a fully relational database.

Firstly, a constellation plot is not really meaningful with RRDTool data as the Data Normalisation has adjusted all data points into a regular series. You can, of course, plot without smoothing and get effectively a bar graph; however, what you are seeing is the RRA summary over a set of adjusted datapoints, not the original samples.

Secondly, RRDTool data is always time series. This is used for the Normalisation step and Rate Calculation (since RRDTool data is always a rate, even when it isn't). So, no, you cannot store generic x values.

I suppose you could store a set of x/y values against a time series, and plot these using a different package, but this would still have data points adjusted to fit the time steps. From what you are asking, I think that it is likely that you need more of a standard database so that you can store exact, unmodified values and graph them using a separate library.