SAA-C03 Design Cost-Optimized Architectures Practice Question

You store application logs in an S3 bucket. After 30 days, the logs are rarely accessed, but you must retain them for 1 year for compliance. Which S3 feature is the best way to reduce storage cost while meeting the retention requirement?

⚠ Common exam trap

A common mix-up: candidates think S3 Standard is always the cheapest option for infrequently accessed data, but they overlook the significant cost savings from lifecycle transitions to colder storage classes like S3 Glacier Deep Archive, which are designed for long-term archival with rare access.

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

✓

Create an S3 lifecycle rule to transition older objects to a colder storage class after 30 days, then expire after 1 year

An S3 Lifecycle rule can automatically transition objects from S3 Standard to a colder storage class (e.g., S3 Glacier Instant Retrieval or S3 Glacier Deep Archive) after 30 days, reducing storage costs for rarely accessed logs. After 1 year, the rule can expire the objects, which permanently deletes them, meeting the compliance retention requirement without manual intervention.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
Create an S3 lifecycle rule to transition older objects to a colder storage class after 30 days, then expire after 1 year
Why this is correct
S3 lifecycle policies can automatically transition objects to lower-cost storage classes based on age. Transitioning after 30 days reduces ongoing storage costs because the logs are rarely accessed, while expiring after 1 year ensures you still meet the compliance retention window.
✗
Keep all logs in S3 Standard and rely on lower request rates to reduce cost
Why it's wrong here
Keeping all logs in S3 Standard while relying on lower request rates ignores the fact that S3 pricing separates storage cost from request cost. The storage cost per GB-month for S3 Standard is substantially higher than that of S3 Standard-IA or Glacier, so even with almost zero GET/PUT requests, your bill stays high simply because you are retaining large volumes of data in the most expensive object storage tier. Since the logs are rarely accessed after 30 days, a lifecycle policy that transitions them to a colder class directly attacks the dominant cost driver—storage footprint—rather than request activity, which is already negligible.
When this WOULD be correct
If the question asked for the cheapest storage for data that is accessed frequently (e.g., daily) and requires low latency, S3 Standard would be the correct choice because it offers high durability and low-latency access without retrieval costs.
✗
Copy logs to EBS snapshots each week and delete the original files
Why it's wrong here
EBS snapshots are designed for point-in-time backups of EBS block storage volumes, not for object-level application log retention. Each snapshot is block-incremental and must be restored to a volume before you can access the files, making log retrieval and analysis cumbersome, and snapshot storage is billed per-GB with no native S3 lifecycle expiration policy. Additionally, deleting the original S3 objects forfeits S3 features such as server-side encryption, object-level versioning, and querying logs directly with Amazon Athena, while introducing new EC2/DLM management overhead—so this approach is both operationally heavier and costlier than a simple S3 lifecycle rule.
When this WOULD be correct
This option would be correct if the question required point-in-time recovery of an EC2 instance's root volume or data volume, with weekly backup snapshots for disaster recovery purposes, and the logs were stored on the instance's EBS volume rather than in S3.
✗
Use S3 replication to a second bucket in another region to reduce costs
Why it's wrong here
S3 Cross-Region Replication (CRR) is a data durability and disaster-recovery feature, not a cost optimization feature. Enabling CRR adds replication request charges, inter-region data transfer charges, and a second storage charge for the replicated objects in the destination bucket; the source object's storage class remains unchanged and still incurs its original fee. Replicating to another region doubles the storage-related costs rather than reducing them, so it cannot be used to lower spend for long-term log retention.
When this WOULD be correct
A question requiring cross-region disaster recovery or compliance with data residency regulations where data must be stored in multiple geographic locations would make S3 replication the correct answer.

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.

✓Create an S3 lifecycle rule to transition older objects to a colder storage class after 30 days, then expire after 1 yearCorrect answer▾

Why this is correct

S3 lifecycle policies can automatically transition objects to lower-cost storage classes based on age. Transitioning after 30 days reduces ongoing storage costs because the logs are rarely accessed, while expiring after 1 year ensures you still meet the compliance retention window.

✗Keep all logs in S3 Standard and rely on lower request rates to reduce costWrong answer — click to see why▾

Why this is wrong here

S3 Standard is the most expensive storage class; relying on lower request rates does not reduce the per-GB storage cost, so it fails to minimize cost for rarely accessed logs.

★ When this WOULD be the correct answer

If the question asked for the cheapest storage for data that is accessed frequently (e.g., daily) and requires low latency, S3 Standard would be the correct choice because it offers high durability and low-latency access without retrieval costs.

Why candidates choose this

Candidates may think that infrequent access automatically reduces cost, overlooking that S3 Standard charges the same storage fee regardless of access frequency.

✗Copy logs to EBS snapshots each week and delete the original filesWrong answer — click to see why▾

Why this is wrong here

Copying logs to EBS snapshots weekly is not cost-effective for long-term retention because EBS snapshots are designed for block-level backups of EC2 instances, not for storing log files. Additionally, this approach incurs ongoing costs for snapshot storage and does not provide native lifecycle management for infrequently accessed data.

★ When this WOULD be the correct answer

This option would be correct if the question required point-in-time recovery of an EC2 instance's root volume or data volume, with weekly backup snapshots for disaster recovery purposes, and the logs were stored on the instance's EBS volume rather than in S3.

Why candidates choose this

Candidates may think that using EBS snapshots is a valid backup strategy for any data, including logs, and that deleting the original files after copying reduces costs, without realizing that S3 lifecycle rules are more cost-effective and purpose-built for log retention.

✗Use S3 replication to a second bucket in another region to reduce costsWrong answer — click to see why▾

Why this is wrong here

S3 replication does not reduce storage costs; it increases them by storing duplicate data in another region. The question asks for cost reduction, not data redundancy or disaster recovery.

★ When this WOULD be the correct answer

A question requiring cross-region disaster recovery or compliance with data residency regulations where data must be stored in multiple geographic locations would make S3 replication the correct answer.

Why candidates choose this

Candidates may confuse replication with cost-saving mechanisms, thinking that moving data to another region automatically reduces costs, or they may overlook the additional storage and transfer fees.

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

Go deeper

SAA-C03 Design Cost-Optimized Architectures Practice Question

Why each option matters

Option-by-option breakdown

Why each answer is right or wrong

AWS S3 Storage Class Comparison

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