Server Thresholds: Breaking Point Physics
Learn the principles of blocking I/O, horizontal scalability limits, and exactly why 5,000 concurrent users will instantly crash a standard Linux machine.
The 1,000 Millisecond Physics Rule
Every single CPU core on planet earth fundamentally only possesses 1,000 milliseconds of compute time per second. You cannot bend this physical law.
If your `Node.js` backend requires EXACTLY `100ms` of processing time to parse data and talk to the database for every single user request... then a single CPU Core can only handle precisely `10` users per second. (1,000 / 100 = 10).
The Equation of Death
If you launch a marketing campaign and 1,000 simultaneous users hit your server at identical RPS (Requests Per Second), your server simply queues them up.
However, 1,000 users × 100ms = 100,000 ms of required work. Your single core only has 1,000 ms to give. Therefore, your server immediately falls 99 seconds behind in the very first second of traffic. The server essentially freezes, user connections timeout (504 Gateway Error), and the application collapses violently.
RAM Starvation (OOM Kill)
To simultaneously hold connection sockets for 1,000 active users, the Linux Kernel spins up processes/threads in RAM. If each user session consumes 50 MB of memory just to format JSON data or manipulate images, you suddenly require 50,000 MB (50 Gigabytes) of RAM.
If your server only has 8 GB of RAM installed, the Linux kernel detects total starvation and violently triggers the OOM (Out of Memory) Killer—a protocol that simply terminates your database and your webserver without warning to save the operating system.