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Chapter IV: Distributed System Concerns

SLA, SLO, SLI

The agreements, objectives, and indicators that define reliability targets.

In short

SLI measures reliability, SLO is the target, and SLA is the contractual promise (with penalties).

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Key takeaways

  • SLI = measurement, SLO = target, SLA = contract.
  • Error budget = 100% − SLO; it balances velocity vs reliability.