The answer is to add a scheduled scaling action for the flash sale, because dynamic scaling policies react to real-time metrics like average CPU utilization, which introduces a lag of several minutes for detection and instance launch, causing requests to fail during sudden traffic spikes. A scheduled scaling action proactively increases capacity before the flash sale begins, ensuring the Auto Scaling group has enough EC2 instances ready to handle the surge immediately. On the AWS Certified SAP on AWS Specialty PAS-C01 exam, this question tests your understanding of predictive versus reactive scaling strategies, with a common trap being to choose a dynamic scaling policy with a lower threshold—this still suffers from the same lag. The key insight is that flash sales are predictable events, so you should schedule capacity ahead of time. Memory tip: “Flash sales need flash foresight—schedule, don’t react.”
PAS-C01 Technology Practice Question
This PAS-C01 practice question tests your understanding of technology. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is running a web application on EC2 instances behind an Application Load Balancer (ALB). The instances are in an Auto Scaling group with a dynamic scaling policy based on average CPU utilization. During a flash sale, the application experiences a sudden spike in traffic, but the Auto Scaling group does not scale out quickly enough, causing some requests to fail. Which solution would improve the scaling responsiveness?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a scheduled scaling action to increase capacity before the flash sale.
Option B is correct because a scheduled scaling action proactively increases capacity before the flash sale, eliminating the lag inherent in dynamic scaling policies. Dynamic scaling reacts to metrics like average CPU utilization, which can take minutes to trigger and propagate, causing request failures during sudden spikes. By pre-scaling, the Auto Scaling group has sufficient instances ready to handle the traffic surge immediately.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Increase the cooldown period for the dynamic scaling policy.
Why it's wrong here
Increasing cooldown delays scaling actions, making it worse.
✓
Add a scheduled scaling action to increase capacity before the flash sale.
Why this is correct
Scheduled scaling proactively adds capacity ahead of known traffic spikes.
Related concept
Read the scenario before looking for a memorised answer.
✗
Decrease the cooldown period for the dynamic scaling policy.
Why it's wrong here
Decreasing cooldown helps react faster but does not proactively prepare for the spike.
✗
Disable scale-in to prevent the Auto Scaling group from terminating instances during the sale.
Why it's wrong here
Disabling scale-in does not help with scaling out more quickly.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often focus on tuning cooldown periods or disabling scale-in, thinking these improve responsiveness, when the real issue is the inherent latency of reactive scaling during unpredictable spikes.
Detailed technical explanation
How to think about this question
Dynamic scaling policies in AWS Auto Scaling rely on CloudWatch alarms that evaluate metrics over a period (e.g., 1-5 minutes) before triggering a scale-out, and then the new instances take additional time to become healthy (e.g., 2-3 minutes for lifecycle hooks and health checks). Scheduled scaling bypasses this latency by using cron-like expressions to adjust desired capacity at a specific time, ensuring capacity is ready before the event. In practice, combining scheduled scaling with dynamic scaling provides both proactive and reactive responsiveness.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Technology — This question tests Technology — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Add a scheduled scaling action to increase capacity before the flash sale. — Option B is correct because a scheduled scaling action proactively increases capacity before the flash sale, eliminating the lag inherent in dynamic scaling policies. Dynamic scaling reacts to metrics like average CPU utilization, which can take minutes to trigger and propagate, causing request failures during sudden spikes. By pre-scaling, the Auto Scaling group has sufficient instances ready to handle the traffic surge immediately.
What should I do if I get this PAS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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