SAA-C03 Practice Question: Unattached EBS volumes continue to incur charges.
A log archive has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances?
⚠ Common exam trap
AWS often tests the misconception that stopping instances or disabling services like CloudTrail reduces storage costs, but the trap here is that only direct actions on the storage resources themselves (deleting volumes and expiring snapshots) affect EBS and snapshot billing.
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
✓
Delete unattached EBS volumes after verifying they are no longer needed
Unattached EBS volumes incur storage costs even when not in use, as EBS pricing is based on provisioned capacity per GB-month. Deleting them after verifying they are no longer needed eliminates this cost without affecting running instances, since attached volumes are untouched. This directly addresses the question's requirement to reduce storage costs without impacting running workloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Stop all EC2 instances in the account
Why it's wrong here
Stopping EC2 instances only halts compute charges for instance usage; all attached EBS volumes, including root volumes, remain fully provisioned and continue to incur per-GiB-month storage fees. Unattached volumes are not automatically created or deleted when an instance stops, so this action does nothing to reduce storage costs from old unattached volumes or stale snapshots. It might even make matters worse by leaving volumes in a stopped state that still bill.
- ✗
Disable CloudTrail logging
Why it's wrong here
CloudTrail logs are metered separately from EBS storage and snapshots, so disabling the audit service has no effect on the charges generated by unattached volumes or expired snapshots. Beyond being irrelevant to storage cost optimization, turning off CloudTrail removes the ability to trace who created, modified, or deleted EBS resources, which is a critical factor for security incident response and compliance. Cost-saving measures should target the actual billable storage resources rather than the monitoring that protects them.
- ✓
Delete unattached EBS volumes after verifying they are no longer needed
Why this is correct
Unattached EBS volumes continue to be billed for their provisioned capacity and IOPS even when no instance is using them; deletion is the only way to eliminate those charges. Before deleting, you must verify that the volume is not needed for data recovery, future instance launches, or as a source for new snapshots. In a log archive scenario, these volumes are prime candidates for deletion because they represent pure waste, and this action directly addresses the cost of the unattached volumes listed in the scenario.
- ✓
Apply snapshot lifecycle policies to expire obsolete snapshots
Why this is correct
Amazon Data Lifecycle Manager (DLM) can apply snapshot lifecycle policies that automatically retain snapshots only for a defined window and then delete them, which directly curbs the cost of accumulating stale snapshots stored in Amazon S3. This is a correct, automated alternative to manual cleanup and enforces consistent data-retention rules without requiring someone to remember to delete old snapshots. It complements volume deletion but is not the same action; it specifically targets the snapshot side of the cost problem.
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 |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.