SAA-C03 Design Resilient Architectures Practice Question
A startup runs a stateless image-resizing API on a fleet of EC2 instances behind an Application Load Balancer. The instances store uploaded source images on their own instance store volumes before processing. During a routine scale-in event, an instance was terminated and several in-flight uploads were lost. The architect must make the design resilient to instance loss without changing the API code. What should the architect do?
⚠ Common exam trap
The trap here is treating instance store as durable because it is physically attached to the instance; instance store data is lost on stop, terminate, or host failure, so it cannot back resilient state.
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
✓
Store uploaded images in Amazon S3 and have instances read from and write to the bucket instead of local disk
The root cause is that uploaded images live on instance store volumes, which are ephemeral and destroyed when an instance terminates. Relocating the source images to Amazon S3 removes the dependency on any single instance and gives the fleet shared, durable storage, so scale-in no longer causes loss. The remaining options delay or observe termination or reduce its frequency, but none preserve the data itself.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Store uploaded images in Amazon S3 and have instances read from and write to the bucket instead of local disk
Why this is correct
Moving the uploaded source images to Amazon S3 decouples the data from any single EC2 instance, so terminating an instance no longer destroys in-flight uploads. S3 provides durable, highly available object storage that all instances can access concurrently. Because the API already treats instances as stateless workers, replacing local storage with S3 is the standard resilience pattern and requires no change to the fleet's scaling behavior.
- ✗
Increase the Auto Scaling group's minimum capacity so that instances are rarely terminated
Why it's wrong here
Raising minimum capacity reduces how often scale-in happens but does not eliminate it, and any instance can still fail unexpectedly or be replaced during a deployment. The images remain tied to individual instance store volumes, which are ephemeral by design and lost on stop, terminate, or host failure. This option lowers probability without providing actual durability.
- ✗
Enable detailed CloudWatch monitoring and create an alarm that notifies operators before scale-in occurs
Why it's wrong here
Monitoring and alarms provide visibility but do not prevent data loss when an instance is terminated. An operator notification still leaves uploaded images on a doomed instance store volume, and scale-in can occur before anyone reacts. This option addresses detection rather than resilience, so in-flight uploads would still be lost during the next scale-in event.
- ✗
Configure an EC2 Auto Scaling lifecycle hook to delay instance termination until uploads complete
Why it's wrong here
A termination lifecycle hook can pause an instance before it is terminated, but it does not preserve data stored on instance store volumes and requires custom logic to drain and migrate in-flight work. The scenario requires resilience without changing application code, and lifecycle hooks alone do not relocate uploaded images. This adds operational complexity without solving the underlying loss of local data.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
Related to this question
About these practice questions
One of 935 original SAA-C03 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.