DBS-C01 Workload-Specific Database Design Practice Question
A company needs to store application logs for 90 days and run periodic analytical queries. The logs are generated at 1 TB per day. Which storage solution is most cost-effective?
⚠ Common exam trap
The trap here is that candidates often over-engineer the solution by choosing a database or data warehouse (like Redshift or RDS) for log storage, forgetting that S3 with S3 Select is purpose-built for cost-effective storage and serverless querying of large datasets with minimal operational 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
✓
Store logs in Amazon S3 and use S3 Select for queries.
Amazon S3 is the most cost-effective storage solution for 90-day retention of 1 TB/day of application logs, as it offers low-cost object storage with lifecycle policies to automatically expire data after 90 days. S3 Select allows you to run analytical queries (e.g., filtering, aggregations) directly on the data stored in S3 using SQL-like statements, without needing to load data into a separate analytics engine, thus minimizing compute costs and operational overhead.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Store logs in Amazon RDS for MySQL with partitioning.
Why it's wrong here
RDS cost is high for 1 TB/day.
- ✗
Store logs in Amazon Redshift with automatic compression.
Why it's wrong here
Redshift is more expensive for raw log storage.
- ✗
Store logs in Amazon DynamoDB with TTL for expiration.
Why it's wrong here
DynamoDB is not ideal for large blobs.
- ✓
Store logs in Amazon S3 and use S3 Select for queries.
Why this is correct
S3 is cost-effective and S3 Select supports queries.
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 DBS-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 DBS-C01 exam.