Balloon goes up comes from WW1[0]. It's a term that, in this instance I suspect means "when shit kicks off", probably world war or armageddon.

Pizza boxes are these: https://en.wikipedia.org/wiki/Pizza_box_form_factor

They're basically saying, when shit hits the fan, they'll be able to rely on these old servers.

Next time ask an LLM.

https://dictionary.cambridge.org/dictionary/english/balloon-...