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.

https://unknownuniverse.uk/tools/proxmox-calculator/