SRE Error Budgets & SLI/SLO Management 2

Question 1

An error budget has been fully consumed three weeks before the end of the quarter. What is the MOST appropriate response?

Accepted Answer

Freeze all non-critical feature releases and focus on reliability work

Answer

When the error budget is exhausted, the standard SRE practice is to halt feature work and redirect engineering effort toward reliability improvements until the budget recovers.

Question 2

Which formula correctly expresses the error budget for a 99.9% monthly SLO?

Accepted Answer

0.1% of total minutes in the month ≈ 43.8 minutes of allowed downtime

Answer

Error budget = (1 − SLO) × measurement window. For 99.9% over ~43,800 minutes/month: 0.001 × 43,800 ≈ 43.8 minutes.

Question 3

A team defines a latency SLI as 'the proportion of homepage requests served in under 200 ms.' Which SLO statement is BEST aligned with this SLI?

Accepted Answer

99% of homepage requests will be served in under 200 ms over a rolling 28-day window

Answer

An SLO must reference the same SLI metric and unit. The SLI is the proportion of requests under 200 ms, so the SLO should set a target percentage for that same proportion over a defined time window.

Question 4

What is the PRIMARY risk of setting SLO targets that are too high (e.g., 99.999%)?

Accepted Answer

The error budget becomes so small that even minor incidents exhaust it, blocking all feature development

Answer

An extremely tight SLO leaves almost no error budget, meaning even routine deployments or brief incidents will exhaust the budget and force a reliability freeze on feature work.

Question 5

A service has two SLIs: availability (target 99.5%) and latency (target 95% of requests under 300 ms). Error budgets are tracked independently. Which statement is TRUE?

Accepted Answer

Exhausting the latency error budget can block releases even if the availability budget still has headroom

Answer

Each SLO has its own independent error budget. If any budget is exhausted, that dimension of reliability is at risk and release decisions should consider halting risky changes regardless of other budgets.

(SRE) Site Reliability Engineering Foundation Certification Practice Test

(SRE) Site Reliability Engineering Foundation Certification Practice Test

SRE Error Budgets & SLI/SLO Management 2