load-testing

name	load-testing
description	Use when: measure system behavior under load to find limits, bottlenecks, and regressions.

Goal: know how the system behaves under realistic and peak load.

Use for:

• validating capacity before a launch or sale
• finding bottlenecks and breaking points
• catching performance regressions

Workflow:

1. Define the scenario: traffic shape, mix, and target SLOs.
2. Model realistic user behavior and data, not uniform hits.
3. Ramp load gradually; record latency percentiles and errors.
4. Push to the breaking point to find the real limit.
5. Correlate results with resource and dependency metrics.
6. Fix the top bottleneck, then re-test.

Measure:

• p50/p95/p99 latency, not just averages
• throughput and error rate under load
• resource saturation (CPU, memory, connections)
• downstream dependency limits

Rules:

• test against a production-like environment and data
• look at tail latency; averages hide pain
• change one variable per run to attribute results
• protect real systems; never load-test production blindly