What you will learn
- Set SLOs from user needs
- Use error budgets
- Balance reliability and features
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The basics, in plain English
Reliability targets are clear numbers that say how dependable a service should be, so the team is not just guessing. They are built from a measured indicator, a target goal, and a small budget for failure. These numbers help decide when to focus on stability versus new features.
- Reliability target
- A specific number describing how dependable a service must be.
- SLI
- The measured number, like the percent of requests that succeed.
- SLO
- The goal you aim for, like 99.9 percent of requests succeeding.
- Error budget
- The small amount of failure allowed before you break the goal.
- Nines
- Shorthand for uptime levels, like “three nines” meaning 99.9 percent.
- Trade-off
- Using the budget to balance shipping features against staying stable.
01
100% is wrong
Perfect reliability is unaffordable and unnecessary. Pick an SLO users accept, then spend the error budget on shipping faster.
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