SRE Capacity Planning & Scaling 4

Question 1

Which of the following best describes 'elastic scaling'?

Accepted Answer

Automatically provisioning and deprovisioning resources in response to real-time demand

Answer

Elastic scaling automatically adjusts resource capacity up or down based on current demand, optimizing both performance and cost.

Question 2

An SRE is capacity planning for a batch processing system that runs nightly. What is the most cost-effective cloud strategy?

Accepted Answer

Use spot/preemptible instances that scale up at night and terminate after completion

Answer

Spot or preemptible instances at scale for short-duration batch jobs significantly reduce cost since the workload is fault-tolerant and time-flexible.

Question 3

What is the purpose of a 'capacity model' in SRE practice?

Accepted Answer

Mapping resource consumption to traffic levels to forecast infrastructure needs

Answer

A capacity model quantifies the relationship between traffic/usage and resource consumption, enabling accurate infrastructure forecasting as load grows.

Question 4

When horizontal scaling is applied to a stateless web tier, what happens to the system's theoretical maximum throughput?

Accepted Answer

It scales linearly with the number of instances (assuming no shared bottleneck)

Answer

Stateless services with no shared state bottleneck scale nearly linearly horizontally because each instance independently handles requests.

Question 5

A service regularly hits its connection pool limit during peak traffic. Which capacity action directly addresses this bottleneck?

Accepted Answer

Increase the database connection pool size or add a connection pooler like PgBouncer

Answer

A connection pool limit is a concurrency bottleneck; increasing pool size or adding a connection pooler like PgBouncer multiplexes connections efficiently.

(SRE) Site Reliability Engineering Foundation Certification Practice Test

(SRE) Site Reliability Engineering Foundation Certification Practice Test

SRE Capacity Planning & Scaling 4