SAA-C03 Design Cost-Optimized Architectures Practice Question
A solutions architect is designing a batch processing workload that runs for 4 hours every night. The workload can be interrupted and resumed without data loss. Cost optimization is a primary requirement for this deployment.
⚠ Common exam trap
SAA-C03 often tests the misconception that Reserved Instances are always the cheapest option, when in fact Spot Instances are far cheaper for interruptible workloads.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure an Auto Scaling group using Amazon EC2 Spot Instances with an appropriate instance diversification strategy.
Spot Instances offer up to 90% discount compared to On-Demand and are ideal for interruptible, resumable batch workloads. Using an Auto Scaling group with instance diversification across multiple instance types and Availability Zones increases the chance of acquiring and retaining Spot capacity, and the workload can tolerate interruptions without data loss. This directly satisfies the cost optimization requirement while maintaining availability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Amazon EC2 Reserved Instances to cover the nightly batch processing requirements over a one-year term.
Why it's wrong here
Reserved Instances are designed for continuous workloads running 24/7 to maximize hourly savings. Because this workload only runs for 4 hours per night, paying for idle capacity during the remaining 20 hours makes Reserved Instances financially inefficient.
- ✗
Provision Amazon EC2 On-Demand Instances and terminate them manually through an AWS Lambda script after completion.
Why it's wrong here
On-Demand instances bill per second while running and offer no discount, and manual termination via Lambda adds no cost benefit over automatic lifecycle management. They are tempting when workloads cannot tolerate interruption, but this batch job explicitly can be interrupted and resumed.
- ✓
Configure an Auto Scaling group using Amazon EC2 Spot Instances with an appropriate instance diversification strategy.
Why this is correct
Spot Instances bill at up to 90% below On-Demand rates and suit interruptible, resumable workloads. Diversifying across instance types and Availability Zones reduces the chance of simultaneous two-minute interruption notices, satisfying the cost-optimisation requirement while tolerating the nightly four-hour job being reclaimed.
- ✗
Purchase Amazon EC2 Dedicated Hosts to run the nightly batch processing instances securely and predictably.
Why it's wrong here
Dedicated Hosts bill per host for the full allocation period regardless of instance usage, defeating cost optimisation for a 4-hour interruptible job. They are tempting when licensing or compliance demands physical server isolation and tenancy visibility.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SAA-C03 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 SAA-C03 exam.