Nevertheless, it is true that Stack Overflow has focused on backend performance and scaled vertically a long way, further than is fashionable. Just not so far as only using two servers for everything.
I'm curious. I saw a similar comment earlier, surely the surely windows licensing is just a drop in the bucket compared to the rest of the infrastructure costs?
I've not really looked at hosting anything on windows before, do they have unusual licensing terms in such a way that it would be a significant cost?
But adding a new server includes having to buy new licenses, which is a consideration you don't have with OSes that under licensing. It costs extra money, and used to be per socket when their infrastructure was conceived.
So what? Licenses are not expensive, especially compared to all of their other costs like the dozens of staff, and paying an invoice isn't complicated. They maintain their own hardware in colocation facilities so they'll get a new license way before they even get the hardware shipped out.
Why does this make scaling out "never an easy option for them"?