The answer is Reserved Instances. This is the correct choice because Reserved Instances provide a significant discount—up to 72% off On-Demand pricing—in exchange for a commitment to a 1- or 3-year term, making them ideal for steady 24/7 workloads with predictable and steady load. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this question tests your ability to match purchasing options to usage patterns, often contrasting Reserved Instances with On-Demand or Spot Instances; a common trap is choosing Spot Instances for cost savings, but those are unsuitable for always-on, critical workloads due to potential interruptions. Remember the memory tip: “Reserve for regular, Spot for spotty”—if your workload runs 24/7 without interruption, Reserved Instances are the cost-optimized path.
SOA-C02 Cost and Performance Optimization Practice Question
This SOA-C02 practice question tests your understanding of cost and performance optimization. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 runs a web application on Amazon EC2 instances that run 24/7. The application has a predictable and steady load. The SysOps administrator wants to minimize compute costs while ensuring the required capacity is always available. Which purchasing option should be used?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "always"
Why it matters: Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Why wrong: On-Demand Instances are flexible but have the highest cost per hour. They are not cost-optimal for a steady 24/7 workload.
B
Reserved Instances
Reserved Instances offer a substantial discount (up to 72%) in exchange for a 1- or 3-year commitment, making them the most cost-effective choice for continuous predictable workloads.
C
Spot Instances
Why wrong: Spot Instances can be terminated at any time by AWS, making them unsuitable for a 24/7 web application that must always be available.
D
Dedicated Hosts
Why wrong: Dedicated Hosts provide physical isolation and are billed per host, which is more expensive than shared tenancy. They are not needed for this use case.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reserved Instances
Reserved Instances (RIs) are the correct choice because the workload runs 24/7 with a predictable and steady load. By committing to a 1- or 3-year term, the company can achieve a significant discount (up to 72%) compared to On-Demand pricing, while ensuring capacity is always available. This aligns with the goal of minimizing compute costs without sacrificing availability.
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.
✗
On-Demand Instances
Why it's wrong here
On-Demand Instances are flexible but have the highest cost per hour. They are not cost-optimal for a steady 24/7 workload.
✓
Reserved Instances
Why this is correct
Reserved Instances offer a substantial discount (up to 72%) in exchange for a 1- or 3-year commitment, making them the most cost-effective choice for continuous predictable workloads.
Clue confirmation
The clue words "always", "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Spot Instances
Why it's wrong here
Spot Instances can be terminated at any time by AWS, making them unsuitable for a 24/7 web application that must always be available.
✗
Dedicated Hosts
Why it's wrong here
Dedicated Hosts provide physical isolation and are billed per host, which is more expensive than shared tenancy. They are not needed for this use case.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose On-Demand Instances for simplicity, overlooking that Reserved Instances provide substantial cost savings for predictable, always-on workloads without any risk of interruption.
Detailed technical explanation
How to think about this question
Reserved Instances apply a billing discount to the underlying EC2 instance usage, not a separate instance type; the discount is applied at the account level based on attributes like instance family, region, and tenancy. For a steady-state workload, Standard RIs offer the highest discount, while Convertible RIs provide flexibility to change instance attributes but at a lower discount. AWS also offers a No Upfront payment option to avoid initial capital outlay, though it results in a slightly higher effective hourly rate than All Upfront or Partial Upfront.
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
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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.
Cost and Performance Optimization — This question tests Cost and Performance Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Reserved Instances — Reserved Instances (RIs) are the correct choice because the workload runs 24/7 with a predictable and steady load. By committing to a 1- or 3-year term, the company can achieve a significant discount (up to 72%) compared to On-Demand pricing, while ensuring capacity is always available. This aligns with the goal of minimizing compute costs without sacrificing availability.
What should I do if I get this SOA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "always", "minimum / minimize". Absolute qualifier. An answer using 'always' is only correct if there are genuinely no exceptions — absolute statements are often wrong in networking.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Variation 1. A company runs a web application on a fleet of Amazon EC2 instances that operate 24/7 with a steady and predictable load. The SysOps administrator wants to minimize compute costs while ensuring the required capacity is always available. Which EC2 purchasing option should the administrator use?
easy
✓ A.Reserved Instances
B.Spot Instances
C.On-Demand Instances
D.Dedicated Hosts
Why A: Reserved Instances (RIs) are the correct choice because the workload runs 24/7 with steady, predictable load. RIs provide a significant discount (up to 72%) over On-Demand pricing in exchange for a one- or three-year commitment, ensuring cost minimization while guaranteeing capacity availability in the specified Availability Zone.
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This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.
Question Discussion
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