SAA-C03 Design Resilient Architectures Practice Question

A company is designing a disaster recovery plan for a critical application hosted on AWS. The application runs on EC2 instances with data stored in Amazon EBS volumes and Amazon S3. The recovery time objective (RTO) is 15 minutes, and the recovery point objective (RPO) is 1 hour. Which three strategies would help meet these objectives? (Choose three.)

⚠ Common exam trap

Watch out — candidates often confuse operational readiness (like pre-provisioning instances) with a specific strategy that directly contributes to meeting RTO/RPO, or they may think Direct Connect is a disaster recovery strategy when it is merely a connectivity option that does not automate failover or data replication.

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 AWS Backup to create hourly snapshots of EBS volumes and copy them to a different AWS Region.

AWS Backup can create hourly snapshots of EBS volumes and copy them to a different AWS Region, meeting the 1-hour RPO by ensuring backups are taken every hour. S3 Cross-Region Replication (CRR) asynchronously replicates objects to a bucket in another region, keeping data synchronized within minutes and supporting the RPO. Amazon Route 53 with a failover routing policy and health checks can automatically redirect traffic to the DR region within seconds to minutes, enabling the 15-minute RTO by quickly failing over to pre-prepared infrastructure.

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 AWS Backup to create hourly snapshots of EBS volumes and copy them to a different AWS Region.
Why this is correct
AWS Backup provides a centralized service to manage backups for various AWS resources, including EBS volumes. Creating hourly snapshots ensures a low Recovery Point Objective (RPO), minimizing potential data loss. Copying these snapshots to a different AWS Region is a fundamental strategy for disaster recovery, enabling the restoration of EBS volumes and associated EC2 instances in an alternate region should the primary region become unavailable.
✗
Pre-provision EC2 instances in the disaster recovery region and keep them running 24/7.
Why it's wrong here
Pre-provisioning and continuously running EC2 instances in a disaster recovery region represents a 'hot standby' strategy. While this approach offers the lowest possible Recovery Time Objective (RTO), it is significantly more expensive due to the ongoing operational costs of maintaining duplicate, fully scaled infrastructure 24/7. For many applications, a more cost-effective strategy like pilot light or warm standby can achieve acceptable RTOs without such high expenditure.
✓
Replicate critical data to S3 in the disaster recovery region using S3 Cross-Region Replication (CRR).
Why this is correct
S3 Cross-Region Replication (CRR) automatically and asynchronously replicates objects between specified S3 buckets in different AWS Regions. This ensures that critical application data stored in S3, such as user-generated content or application assets, is continuously available in the disaster recovery region. CRR is a highly effective and managed service for maintaining data durability and availability, crucial for rapid recovery during a regional outage.
✗
Store Amazon Machine Images (AMIs) in the source region and use AWS Lambda to copy them after a disaster.
Why it's wrong here
Storing Amazon Machine Images (AMIs) only in the source region and attempting to copy them via AWS Lambda *after* a disaster introduces significant delays, severely impacting the Recovery Time Objective (RTO). AMIs are region-specific, and for an effective disaster recovery strategy, pre-copying or regularly replicating AMIs to the DR region is essential. Relying on post-disaster replication would prolong recovery efforts unnecessarily.
✓
Configure Amazon Route 53 with a failover routing policy and health checks to redirect traffic to the DR region.
Why this is correct
Amazon Route 53's failover routing policy, combined with robust health checks, is a critical component for automated disaster recovery. It continuously monitors the health of resources in the primary region and, upon detecting a failure, automatically redirects DNS traffic to the healthy resources in the disaster recovery region. This mechanism ensures high availability and minimizes downtime by transparently directing users to the operational application endpoint.
✗
Set up an AWS Direct Connect link between the primary and DR regions for faster data transfer.
Why it's wrong here
AWS Direct Connect establishes a dedicated, private network connection from an on-premises data center directly to AWS. It is designed for hybrid cloud architectures, not for inter-region connectivity *between* two AWS Regions. Data transfer and communication between different AWS Regions occur over the highly resilient AWS global network, often utilizing services like VPC peering or AWS Transit Gateway, making Direct Connect irrelevant for this specific inter-region DR scenario.

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

SAA-C03 Design Resilient Architectures Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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