SAA-C03 Design Cost-Optimized Architectures Practice Question
A log archive has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The design must avoid adding custom operational scripts.
⚠ Common exam trap
Many exam-takers confuse stopping instances (which does not delete volumes or snapshots) with deleting resources, or think disabling CloudTrail reduces storage costs, when in fact CloudTrail logs are stored in S3, not EBS, and have separate cost implications.
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
Deleting unattached EBS volumes eliminates storage costs for volumes that are not in use, and since they are not attached to any running instance, this action does not affect running instances. Option D is correct because applying snapshot lifecycle policies automates the deletion of obsolete snapshots, reducing storage costs without requiring custom scripts or impacting running instances.
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 all EC2 instances does not reduce EBS storage costs because the underlying block storage volumes remain allocated and continue to incur per-GB-month charges independent of the instance state. Moreover, stopping instances does nothing to delete old snapshots, which are billed separately, and it unnecessarily disrupts production workloads if any are still running. A targeted approach is to identify and delete only unused volumes and snapshots.
- ✗
Disable CloudTrail logging
Why it's wrong here
Disabling CloudTrail logging is not a storage cost optimization for EBS because CloudTrail records API activity and its costs are unrelated to volume or snapshot storage. Even with CloudTrail disabled, unattached volumes and stale snapshots continue to accrue charges at the same rate. Disabling auditing also weakens your governance and security posture, potentially masking unapproved API calls or resource deletions, and it fails to address the actual drivers of EBS cost.
- ✓
Delete unattached EBS volumes after verifying they are no longer needed
Why this is correct
Unattached EBS volumes in the 'available' state still incur full storage charges because EBS billing is based on provisioned capacity, not on whether the volume is attached to an instance. Before deleting, you should verify the volume is no longer needed (e.g., it is not the boot volume of a stopped instance or referenced in a launch template). You can also create a final snapshot for backup, but deleting the volume itself is what stops recurring costs.
- ✓
Apply snapshot lifecycle policies to expire obsolete snapshots
Why this is correct
Snapshot lifecycle policies, such as those in Amazon Data Lifecycle Manager (DLM), can automatically schedule the expiration of obsolete snapshots based on age, count, or custom tags. Since snapshots are stored in Amazon S3 and billed per GB-month, deleting stale snapshots directly reduces storage costs. This option is correct because it targets the snapshot component of the problem, rather than the underlying volumes, and automates cleanup to prevent future accumulation.
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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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.