Stack Overflow also famously buys the biggest hardware they can get and upgrade their database server accordingly.
I always wonder if horizontal scaling is really always the right answer, when you can just buy a bigger box (of bigger VM) and spare yourself a lot of issues.
I work for a large CDN, with many thousands of servers pushing near line-rate out of our NICs... we certainly can't vertically scale that.
There is a limit to how much you can vertically scale.
Even for the things we CAN vertically scale, we need to be able to handle hardware failure and OS upgrades without taking any downtime, so you are going to need to be able to horizontally scale enough to handle that.
A CDN is essentially "horizontal scale as a service". The vast majority of products are very different.
I don’t think we are unique, though, and there are many engineers on here who work at all sorts of interesting places with non-standard workloads. I was just pointing out the reasons we can’t vertically scale.
Today you can without issues have 128 cores and 1TB RAM in one server (or 48 cores and 1.5TB memory if you prefer Intel). Of course not everything scales perfectly, but you can get pretty far before you are really forced to scale horizontally.
Horizontally scaling your database is a last resort used at truly mindboggling scales.
Especially with today’s hardware or simple cloud vms you’ll come a long way.
There's interesting tech out there, but I think adding "interesting" technology to your stack without a very good reason is usually a mistake.
"Keep your architecture as simple as possible, but no simpler". There are important problems kafka solves. But its worth checking if you have one of those problems before using it.
But I also tend to think "you can always get a bigger box" can take you pretty far, and much further than most people that only think in terms of AWS realize.