DVA-C02 Troubleshooting and Optimization Practice Question
A company is using Amazon S3 to store large objects. Users report that uploads are slow. Which THREE actions should the developer take to optimize upload performance?
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
✓
Use multipart upload for objects over 100 MB.
Multipart upload improves throughput for large objects over 100 MB by uploading parts in parallel. Option C is correct because S3 Transfer Acceleration uses CloudFront edge locations to reduce latency for uploads over long distances. Option E is correct because using multiple S3 prefixes (i.e., parallelizing requests across different key prefixes) can increase the request rate and overall throughput. Option B is incorrect because S3 Select is used to retrieve subsets of data from an object, not to upload. Option D is incorrect because transitioning to S3 Glacier is for data lifecycle management, not for improving upload performance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use multipart upload for objects over 100 MB.
Why this is correct
Multipart upload splits a large object into independent parts that are uploaded in parallel, which dramatically increases throughput and enables efficient retries for individual failed parts. The AWS SDKs automatically apply multipart upload when an object exceeds the 100 MB threshold, and it is the recommended approach for objects over 100 MB because it also allows you to pause and resume uploads, reducing the impact of network interruptions.
- ✗
Use S3 Select to upload only specific parts of the object.
Why it's wrong here
S3 Select is a query-in-place feature that lets you retrieve only a subset of an object's data by running SQL expressions against the object's contents, primarily to reduce the amount of data transferred during reads. It has absolutely no role in the upload path; you cannot use S3 Select to write, modify, or upload specific parts of an object. Uploading partial data requires either range PUTs or multipart upload, not S3 Select.
- ✓
Enable S3 Transfer Acceleration.
Why this is correct
S3 Transfer Acceleration uses AWS edge locations and the global Amazon backbone network to route uploads over optimized paths, substantially reducing latency and improving upload speeds, especially for clients geographically distant from the destination bucket. The feature requires a special accelerate endpoint (e.g., bucket.s3-accelerate.amazonaws.com) and can only speed up uploads; it does not accelerate downloads or other operations.
- ✗
Transition objects to S3 Glacier after upload.
Why it's wrong here
Transitioning objects to S3 Glacier via lifecycle policies moves data to colder storage classes for cost savings, but it is an asynchronous, background operation that occurs after the object has already been uploaded. The storage class chosen for the destination does not affect the upload path, network throughput, or how quickly data is ingested; upload speed is governed by factors like multipart upload, Transfer Acceleration, and the underlying network conditions.
- ✓
Use multiple S3 prefixes to increase request rate.
Why this is correct
Spreading upload requests across multiple S3 prefixes (key name prefixes) increases the request rate your bucket can handle. S3 historically scales to about 3,500 PUT/POST/DELETE requests per second and 5,500 GET requests per second per prefix, so using multiple prefixes—such as date, region, or a random hash—distributes the load and avoids throttling. This is a key performance best practice for high-throughput uploads, though the exact per-prefix limits have evolved with S3's architecture.
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 DVA-C02 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 DVA-C02 exam.