It's intended to run without maintenance for five years. That's been tried before. InfoSeek did it in the early days of search engines. They didn't repair machines; the entire module of some number of racks was replaced at end of life. But that idea seems to have fallen out of fashion. That Microsoft is trying this again is significant.
It's running in dry nitrogen. That has advantages over air. No corrosion, for one.
It's running in dry nitrogen. That has advantages over air. No corrosion, for one.