PAS-C01 Operations and Maintenance Practice Question
A company has a production AWS account that contains an Amazon RDS for MySQL DB instance. The database is critical and must have automated backups enabled with a retention period of 30 days. The company also requires point-in-time recovery to any second within the retention period. The operations team has configured automated backups with a retention period of 30 days, but they notice that the automated backups are not being taken consistently. The DB instance is in a Multi-AZ deployment and has a storage size of 500 GB. The team checks the backup window and finds that it is set to 02:00-03:00 UTC. The backup window is non-overlapping with the maintenance window. The DB instance is actively used during the backup window with heavy write traffic. Which of the following is the MOST likely reason for the inconsistent automated backups?
⚠ Common exam trap
The trap here is that candidates may overlook the impact of heavy write traffic on backup consistency, assuming that Multi-AZ or non-overlapping windows guarantee reliable backups, or mistakenly think that storage size limits or Multi-AZ incompatibility are the root cause.
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 heavy write traffic during the backup window causes I/O suspension and backup failures.
The heavy write traffic during the backup window causes I/O suspension, which can lead to backup failures. When an RDS for MySQL DB instance experiences high write activity during a backup, the backup process may be delayed or fail due to I/O suspension, especially if the instance is under heavy load. This is because automated backups require a consistent snapshot, and excessive write I/O can prevent the snapshot from completing within the backup window.
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 storage size of 500 GB exceeds the maximum backup size limit.
Why it's wrong here
The maximum backup size is 16 TB for RDS MySQL, so 500 GB is well below the limit.
- ✓
The heavy write traffic during the backup window causes I/O suspension and backup failures.
Why this is correct
High write activity can interfere with the backup process, leading to failures.
- ✗
The Multi-AZ deployment does not support automated backups.
Why it's wrong here
Multi-AZ deployments fully support automated backups.
- ✗
The backup window overlaps with the maintenance window.
Why it's wrong here
The problem states the windows are non-overlapping.
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 PAS-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 PAS-C01 exam.