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PROFESSIONAL-CLOUD-DEVOPS-ENGINEER · Question #125

You support a high-traffic web application and want to ensure that the home page loads in a timely manner. As a first step, you decide to implement a Service Level Indicator (SLI) to represent home pa

The correct answer is C. Count the number of home page requests that load in under 100 ms, and then divide by the total. Google recommends defining SLIs as a ratio of 'good events' to total events. For latency, a 'good event' is a request that completes within the acceptable threshold (100 ms). The SLI is therefore: (number of requests completing under 100 ms) / (total number of requests). This pro

Submitted by javi_es· Apr 18, 2026Applying site reliability engineering principles to a service

Question

You support a high-traffic web application and want to ensure that the home page loads in a timely manner. As a first step, you decide to implement a Service Level Indicator (SLI) to represent home page request latency with an acceptable page load time set to 100 ms. What is the Google-recommended way of calculating this SLI?

Options

  • ABucketize the request latencies into ranges, and then compute the percentile at 100 ms.
  • BBucketize the request latencies into ranges, and then compute the median and 90th percentiles.
  • CCount the number of home page requests that load in under 100 ms, and then divide by the total
  • DCount the number of home page request that load in under 100 ms, and then divide by the total

How the community answered

(53 responses)
  • A
    6% (3)
  • B
    9% (5)
  • C
    83% (44)
  • D
    2% (1)

Explanation

Google recommends defining SLIs as a ratio of 'good events' to total events. For latency, a 'good event' is a request that completes within the acceptable threshold (100 ms). The SLI is therefore: (number of requests completing under 100 ms) / (total number of requests). This produces a proportion between 0 and 1 that is easy to track against an SLO. Options A and B describe distribution/percentile analysis, which are useful for investigation but not the recommended SLI formula. Option D is a duplicate of C with a typo and is the distractor - C is the correctly worded answer.

Topics

#Service Level Indicator (SLI)#Latency#Site Reliability Engineering (SRE)#Performance Monitoring

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