Every guide I write ends in the same handful of questions. How much hardware do I actually need? What happens when one box dies? Are my backups real or just a feeling? A guide can walk you through a setup, but it can't do arithmetic about your lab — so I built eleven small tools that can, at peira.dev/tools . They're free, none ask who you are, and seven of the eleven keep working once the page has loaded — network unplugged, laptop in a cupboard, whatever. They share one lab p...