SAA-C03 Design Cost-Optimized Architectures Practice Question
A SaaS company uses an S3 bucket for database backups created daily. Backups are rarely restored; the company’s documented RTO is 24 hours, and the compliance policy requires backups be kept for 90 days. The team currently stores all backups in S3 Standard, which is costly.
Which single lifecycle policy change is most cost-optimized while still meeting the 24-hour RTO and 90-day retention?
⚠ Common exam trap
Watch out — candidates often choose S3 Glacier Deep Archive for maximum cost savings without considering that its standard retrieval time (12 hours) could fail to meet the 24-hour RTO under load or without expedited retrieval, which adds cost and complexity.
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
✓
Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Flexible Retrieval, and keep them until day 90.
S3 Glacier Flexible Retrieval offers retrieval times ranging from minutes to hours, which comfortably meets the 24-hour RTO, while providing significant cost savings over S3 Standard for data that is rarely accessed. Transitioning backups older than 1 day to this storage class reduces costs without compromising the 90-day retention requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Flexible Retrieval, and keep them until day 90.
Why this is correct
Glacier Flexible Retrieval is intended for backups with infrequent access and supports restores within an RTO measured in hours.
- ✗
Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Instant Retrieval, and keep them until day 90.
Why it's wrong here
Instant Retrieval can meet the RTO but usually costs more than Flexible Retrieval for infrequent backups.
When this WOULD be correct
If the RTO were reduced to minutes (e.g., 5 minutes) and backups needed immediate retrieval for frequent restores, Glacier Instant Retrieval would be the correct choice to meet the low-latency requirement while still being cheaper than S3 Standard.
- ✗
Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Deep Archive, and keep them until day 90 with no restore configuration.
Why it's wrong here
Deep Archive restore times are typically longer and may conflict with a strict 24-hour RTO expectation.
When this WOULD be correct
A question where the RTO is greater than 48 hours (e.g., 72 hours) and the retention period is long (e.g., 1 year), and cost optimization is the primary goal, would make Glacier Deep Archive the correct choice.
- ✗
Add a lifecycle rule to transition backups older than 1 day to S3 One Zone-IA, and delete them after 7 days.
Why it's wrong here
One Zone-IA reduces cost but deletion after 7 days breaks the required 90-day retention.
When this WOULD be correct
This option would be correct if the compliance policy required retention for only 7 days and the RTO was less than 1 hour, allowing quick retrieval from One Zone-IA at lower cost than Standard, and if the data was non-critical and could tolerate AZ-level failures.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.
✓Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Flexible Retrieval, and keep them until day 90.Correct answer▾
Why this is correct
Glacier Flexible Retrieval is intended for backups with infrequent access and supports restores within an RTO measured in hours.
✗Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Instant Retrieval, and keep them until day 90.Wrong answer — click to see why▾
Why this is wrong here
Glacier Instant Retrieval has a higher storage cost than Glacier Flexible Retrieval and does not provide significant cost savings for backups that are rarely restored, making it less cost-optimized for this scenario.
★ When this WOULD be the correct answer
If the RTO were reduced to minutes (e.g., 5 minutes) and backups needed immediate retrieval for frequent restores, Glacier Instant Retrieval would be the correct choice to meet the low-latency requirement while still being cheaper than S3 Standard.
Why candidates choose this
Candidates may confuse 'Instant Retrieval' with 'Flexible Retrieval' and assume that 'Instant' is always better, overlooking the cost implications and the fact that the RTO of 24 hours allows for slower retrieval.
✗Add a lifecycle rule to transition backups older than 1 day to S3 Glacier Deep Archive, and keep them until day 90 with no restore configuration.Wrong answer — click to see why▾
Why this is wrong here
Glacier Deep Archive has a retrieval time of 12-48 hours, which exceeds the 24-hour RTO, making it unsuitable for this requirement.
★ When this WOULD be the correct answer
A question where the RTO is greater than 48 hours (e.g., 72 hours) and the retention period is long (e.g., 1 year), and cost optimization is the primary goal, would make Glacier Deep Archive the correct choice.
Why candidates choose this
Candidates may choose this because Glacier Deep Archive is the cheapest storage class, and they overlook the RTO constraint, assuming any glacier class meets the requirement.
✗Add a lifecycle rule to transition backups older than 1 day to S3 One Zone-IA, and delete them after 7 days.Wrong answer — click to see why▾
Why this is wrong here
S3 One Zone-IA does not meet the 90-day retention requirement because the rule deletes objects after 7 days. Additionally, One Zone-IA is not resilient to AZ failures, which could risk backup availability within the 24-hour RTO.
★ When this WOULD be the correct answer
This option would be correct if the compliance policy required retention for only 7 days and the RTO was less than 1 hour, allowing quick retrieval from One Zone-IA at lower cost than Standard, and if the data was non-critical and could tolerate AZ-level failures.
Why candidates choose this
Candidates may choose this option because S3 One Zone-IA offers lower storage cost than Standard, and they overlook the 90-day retention requirement or mistakenly think the 7-day deletion can be adjusted, or they underestimate the importance of durability for backups.
Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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.