DEA-C01 Data Operations and Support Practice Question
A data engineer is managing an Amazon Redshift cluster and needs to load data from Amazon S3. The engineer uses the COPY command but encounters the error: 'S3ServiceException: Access Denied.' The Redshift cluster has an IAM role attached with permissions to access the S3 bucket. What is the most likely cause of this error?
⚠ Common exam trap
The trap here is focusing only on the IAM role's permissions and ignoring the S3 bucket policy, which can also deny 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
✓
The S3 bucket policy does not grant access to the IAM role used by Redshift.
The Access Denied error from S3 during a COPY operation typically indicates that the IAM role used by Redshift does not have sufficient permissions, or the S3 bucket policy does not allow the role. Even if the role has an S3 policy, an explicit deny or missing allow in the bucket policy can cause this. The engineer should verify both the IAM role's policies and the S3 bucket policy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The IAM role attached to the Redshift cluster does not have the correct trust relationship with Redshift.
Why it's wrong here
The trust relationship allows Redshift to assume the role. If it were incorrect, the role could not be assumed at all, and the error might be different (e.g., 'User is not authorized to perform: sts:AssumeRole'). Since the role is attached and permissions are granted, the trust relationship is likely correct. The Access Denied error points to S3 permissions.
- ✗
The Redshift cluster is not in the same AWS Region as the S3 bucket.
Why it's wrong here
Redshift can load data from S3 buckets in different Regions, but there may be data transfer costs. The COPY command supports cross-Region loads. An Access Denied error is not caused by Region mismatch; it is an authorization issue. Region mismatch would typically result in a different error or no error at all.
- ✗
The COPY command is missing the CREDENTIALS parameter.
Why it's wrong here
When using an IAM role, the COPY command must include the IAM_ROLE parameter, not CREDENTIALS. If the IAM_ROLE parameter is missing, Redshift cannot assume the role, leading to an access error. However, the scenario states the cluster has an IAM role attached, implying the command likely includes it. The Access Denied error specifically suggests the role lacks S3 permissions or the bucket policy blocks it.
- ✓
The S3 bucket policy does not grant access to the IAM role used by Redshift.
Why this is correct
Even if the IAM role has S3 permissions, the S3 bucket policy must also allow access from that role. If the bucket policy explicitly denies or does not allow the role, Redshift will receive an Access Denied error. This is a common misconfiguration when the bucket is in a different account or has restrictive policies.
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
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This DEA-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 DEA-C01 exam.