Manuals / Performance Testing Basics / Ch 2

A · Define goodBeginner35 min read

2. SLIs, SLOs & user perception

Performance Testing Basics · 36 pages source format

SLI = what you measure. SLO = target. Latency percentiles (p95/p99) beat averages. Errors and saturation complete the picture.

What you'll learn

  • Latency percentiles
  • Availability
  • Apdex lite

Define SLIs

For your journey: success rate, latency p95, maybe throughput.

  • Latency — p50/p95/p99
  • Errors — 5xx / business failures
  • Saturation — CPU, pool, queue depth

Do this now

Write SLIs + draft SLO (e.g. p95 < 500ms at X RPS). Note confidence.

Clear?

Checklist