Ah, thanks for the clarification. I'm unsure how their Perl script renders images (if it draws them every time or if they're stored and retrieved) but at 4 requests a minute, I don't think it'd cause NFO any performance problems but I'm not entirely sure.
Also, to NFO staff, my GET bot uses "Open Local Network Operations Centre" in the User agent so you can easily identify bot traffic

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Glad to see you too are still coding your libraries and good luck to you with them - and also good luck with uni.
Personally I'm thinking of treating myself to an ultrawide monitor that'll be placed portrait in my office so I can have a large overview of my service traffic to easily spot when things might need intervention. That's what I'll be using the graphs in the image for
