SOA-C02 Reliability and Business Continuity Practice Question
A SysOps administrator needs to ensure that an Amazon S3 bucket can withstand the loss of an entire AWS Availability Zone. What is the SIMPLEST configuration to meet this requirement?
⚠ Common exam trap
The trap here is that candidates often overthink and choose cross-region replication (Option A) for high availability, but the question specifically asks for resilience against an AZ loss, which S3 Standard already provides within a single Region without the complexity and cost of CRR.
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 S3 Standard storage class.
S3 Standard automatically stores objects across a minimum of three Availability Zones (AZs) within the same AWS Region. This design ensures that the bucket can withstand the loss of an entire AZ without any additional configuration, making it the simplest option to meet the requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable cross-region replication to a bucket in another Region.
Why it's wrong here
Enabling cross-region replication (CRR) copies objects to a bucket in a separate AWS Region for disaster recovery or compliance, but it does nothing to change how the source bucket stores objects within the source Region. CRR is asynchronous and introduces added cost, bandwidth usage, and replication lag, while the source bucket's resilience to an individual Availability Zone failure still depends entirely on the storage class of the source objects. It is therefore overkill for this requirement when S3 Standard already provides the needed AZ-level redundancy.
- ✓
Use S3 Standard storage class.
Why this is correct
The S3 Standard storage class is the correct choice because it automatically stores each object redundantly across a minimum of three Availability Zones in the same AWS Region. S3 Standard is engineered for 99.999999999% (11 nines) object durability and 99.99% availability, so if one Availability Zone becomes unavailable, S3 can continue serving reads and writes from the remaining AZs without any administrative action. This built-in synchronous replication across AZs is precisely what satisfies the requirement for AZ failure resilience.
- ✗
Use S3 One Zone-IA storage class.
Why it's wrong here
S3 One Zone-IA places objects in only a single Availability Zone, making it unsuitable for any requirement to survive an entire AZ failure. If the underlying AZ fails or is destroyed, all objects stored with the One Zone-IA storage class are permanently lost. It is intended only for rarely accessed, easily re-creatable data, and it explicitly lacks the cross-AZ redundancy that S3 Standard provides.
- ✗
Enable MFA Delete on the bucket.
Why it's wrong here
MFA Delete is a bucket-level versioning safeguard that requires a second authentication factor to permanently delete an object version or change the versioning state, protecting against accidental or malicious deletion. It has no impact on how S3 physically stores or replicates data across Availability Zones, so it cannot help meet an availability-zone resilience requirement. This option addresses a different problem entirely: data destruction prevention, not infrastructure redundancy.
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 by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-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 SOA-C02 exam.