- A
Amazon CloudWatch Logs
Why wrong: CloudWatch Logs is for real-time monitoring, not cost-effective long-term storage.
- B
Amazon Redshift
Why wrong: Redshift is expensive for storing raw logs.
- C
Amazon Athena
Athena can query logs directly on S3.
- D
Amazon Kinesis Data Streams
Why wrong: Kinesis is for real-time streaming, not storage.
- E
Amazon S3
S3 is low-cost storage for log archives.
Question 1,482 of 1,755
MLS-C01 Data Engineering Practice Question
This MLS-C01 practice question tests your understanding of data engineering. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company wants to centralize logging from multiple AWS accounts and on-premises servers. The logs must be stored cost-effectively and be searchable. Which TWO services should be used? (Choose TWO.)
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
✓
Amazon Athena
Amazon S3 (option E) provides a cost-effective, durable storage layer for centralized logs, while Amazon Athena (option C) enables serverless SQL-based searching directly on the log data stored in S3 without needing to load it into a separate database. Together, they allow you to store logs cheaply and query them on demand, meeting the requirements of cost-effectiveness and searchability.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon CloudWatch Logs
Why it's wrong here
CloudWatch Logs is for real-time monitoring, not cost-effective long-term storage.
- ✗
Amazon Redshift
Why it's wrong here
Redshift is expensive for storing raw logs.
- ✓
Amazon Athena
Why this is correct
Athena can query logs directly on S3.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon Kinesis Data Streams
Why it's wrong here
Kinesis is for real-time streaming, not storage.
- ✓
Amazon S3
Why this is correct
S3 is low-cost storage for log archives.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Amazon CloudWatch Logs with a centralized log storage solution, but it is actually a real-time monitoring service with high storage costs, not a cost-effective long-term archive; similarly, Kinesis Data Streams is mistaken for a storage service when it is purely a streaming ingestion layer.
Detailed technical explanation
How to think about this question
Athena uses Presto under the hood to execute SQL queries directly on data stored in S3, supporting formats like Parquet, ORC, and JSON, which allows you to partition logs by date or account for efficient querying. S3’s lifecycle policies can automatically transition older logs to Glacier or Deep Archive for further cost savings, while Athena’s per-query pricing means you only pay for the data scanned, making it ideal for infrequent, exploratory searches. A real-world scenario is a security team centralizing VPC Flow Logs and CloudTrail logs from multiple accounts into a single S3 bucket, then using Athena to run forensic queries without provisioning any servers.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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 |
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this MLS-C01 question test?
Data Engineering — This question tests Data Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon Athena — Amazon S3 (option E) provides a cost-effective, durable storage layer for centralized logs, while Amazon Athena (option C) enables serverless SQL-based searching directly on the log data stored in S3 without needing to load it into a separate database. Together, they allow you to store logs cheaply and query them on demand, meeting the requirements of cost-effectiveness and searchability.
What should I do if I get this MLS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jul 4, 2026
This MLS-C01 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 MLS-C01 exam.
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