After coming close to running out of resources last week and having to re-purpose another device turning it into a 3rd Proxmox node, it got me thinking about how easily ZFS ARC cache and VM overhead sneak up on you.
So, I built a basic tool for rough guidance.
It calculates vCPU overcommit ratios and RAM allocation locally in your browser. Just pure client-side math so you don’t accidentally OOM your hypervisor like I almost did. Inputs stay right in your browser and aren’t saved anywhere.
Feedback or sanity checks on the math are welcome.

I’m new to this hobby and have only dipped my toes, but please tell me “out of mana” is a commonly accepted shorthand for this problem, because I love it
Out Of Memory, but you can choose to believe what you like
Lol, that makes way more sense, thank you. Clearly hadn’t had enough coffee this morning!
no no… you’re onto something