back-of-the-envelope

This skill should be used when the user needs to "estimate QPS", "back-of-the-envelope" (BOTEC) numbers, "how much storage / bandwidth", "how many servers", "peak load", "capacity planning", or wants the standard latency / throughput / availability numbers to ground a design (latency table, QPS rates, powers of two, nines). Use it whenever a design decision hinges on scale — convert any "high traffic" / "huge data"…