For instance, you let mrtg make yearly graphs about loadavg. Almost always, your loadavg is less than 2, but you are very interested in seeing when it's close to 2 and when it's below 1. But 6 months ago, an application went haywire, forked itself too many times, and your load avg briefly approached 100. Your yearly graph is now worthless, as that single spike dominates the picture, turning your graph almost into a representation of a Dirac function. You can prevent yourself against that by having mrtg discard too high values, but then you have no history of the event. It doesn't allow to ignore spikes when displaying the results.

Anyway, this rant has little to do with Perl. Except that I've written plotting applications many times in Perl, and I vastly prefer them over mrtg. I never use any plotting modules in my Perl program - I always open a pipe to gnuplot.

Abigail