Examkin

Soru

Zorluk: OrtaDefining and Managing SLOs, SLIs, and Error Budgets

An enterprise healthcare provider operates an electronic health records (EHR) API Gateway on Google Cloud with a defined Service Level Objective (SLO) of 99.9%99.9\% availability over a rolling 3030-day window (43,20043,200 minutes). Over the current 3030-day window, the service experienced two incidents while maintaining constant request volume: a database outage resulted in a complete service failure (100%100\% error rate) lasting 1515 minutes, and a downstream service throttling issue resulted in a partial degradation (40%40\% error rate) lasting 4545 minutes. What is the remaining allowable error budget in minutes for this 3030-day window?

Cevap: 10.2 minutes

Cevap

The remaining allowable error budget for the 30-day window is 10.2 minutes.
The total allowable error budget for a 99.9% SLO over 30 days (43,200 minutes) is 0.001×43,200=43.20.001 \times 43,200 = 43.2 minutes. Incident 1 (100% failure for 15 minutes) consumes 15.0 minutes. Incident 2 (40% failure for 45 minutes under uniform traffic) consumes 45×0.40=18.045 \times 0.40 = 18.0 minutes. Total consumed budget is 15.0+18.0=33.015.0 + 18.0 = 33.0 minutes. Subtracting the consumed budget from the total allowable budget leaves 43.2−33.0=10.243.2 - 33.0 = 10.2 minutes.

Adım Adım Çözüm

1
Calculate the total allowable error budget for a 99.9% availability SLO over 30 days (43,200 minutes).
Total Error Budget = 43,200×(1−0.999)=43.243,200 \times (1 - 0.999) = 43.2 minutes.
An SLO of 99.9% permits a maximum error rate of 0.1% across the entire rolling window.
2
Compute the effective downtime minutes consumed during the total outage incident.
Incident 1 Budget Consumed = 15 minutes×100%=15.015 \text{ minutes} \times 100\% = 15.0 minutes.
A 100% error rate for 15 minutes consumes 15 full minutes of error budget.
3
Compute the effective downtime minutes consumed during the degraded state incident.
Incident 2 Budget Consumed = 45 minutes×40%=18.045 \text{ minutes} \times 40\% = 18.0 minutes.
Under uniform traffic, a partial outage with a 40% error rate for 45 minutes consumes equivalent error budget proportional to the failure fraction (45×0.4045 \times 0.40).
4
Sum the error budget consumed across both operational incidents.
Total Consumed = 15.0+18.0=33.015.0 + 18.0 = 33.0 minutes.
Combining the impact of full and partial outages gives the total budget spent.
5
Subtract total consumed budget from total allowable budget.
Remaining Error Budget = 43.2−33.0=10.243.2 - 33.0 = 10.2 minutes.
This yields the remaining margin of unreliability permitted before breaching the SLO target.

Anahtar Kavram

SLO Error Budget Calculation for Partial and Total Outages
Bu soruyu puanla

Konular

Defining and Managing SLOs, SLIs, and Error Budgets

Bu konudan daha fazla soru