There are plenty of debates and talks about monolithic vs microservices touting the benefits of each. Most such talks seem to indicate that monolithic apps scale badly. By that they probably mean horizontal scaling && developers/teams scaling, but we have good options for vertical scaling these days via monstrous VMs with high RAM/CPU from almost all cloud providers.

What is the biggest (scale) application(s) that you have personally seen or worked with in a single VM or baremetal server ?

The scale could be in terms of maximum requests per second, volume of data transferred, maximum parallel connections, etc.

The most popular example that I could think of is Expensify where they handle 4million qps in a single monster machine with 1TB RAM via Bedrockdb https://blog.expensify.com/2018/01/08/scaling-sqlite-to-4m-qps-on-a-single-server/

I am looking for similar examples of big products on a single machine or VM. Not on a super-computer, mainframe, specialised appliances (like SAP HANA), etc. but normal X86 boxes or cloud VMs. I am curios to know how much of HN crowd choose these over complex things like Kubernetes and their thoughts on these.