We “solved” C10K years ago yet we keep reinventing it

This article explains problems that still show up today under different names.

C10K wasn’t really about “handling 10,000 users” it was about understanding where systems actually break: blocking I/O, thread-per-connection models, kernel limits, and naive assumptions about hardware scaling.

What’s interesting is how often we keep rediscovering the same constraints:

• event loops vs threads
• backpressure and resource limits
• async abstractions hiding, not eliminating, complexity
• frameworks solving symptoms rather than fundamentals

Modern stacks (Node.js, async/await, Go, Rust, cloud load balancers) make these problems easier to use, but the tradeoffs haven’t disappeared they’re just better packaged.

With some distance, this reads less like history and more like a reminder that most backend innovation is iterative, not revolutionary.