SAA-C03 Design Resilient Architectures Practice Question
A company runs a stateful workload on Amazon EC2 instances in an Auto Scaling group. The workload writes session data to the instance store and to an Amazon EBS volume attached at launch. The company wants the workload to survive an Availability Zone failure without losing session data. What should the solutions architect do?
⚠ Common exam trap
The trap here is assuming that EBS snapshots, RAID, or termination protection can preserve live session data when an entire Availability Zone fails.
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
✓
Move session data to Amazon ElastiCache for Redis with Multi-AZ enabled, and configure the Auto Scaling group to span multiple Availability Zones.
Session data must be moved off instance-bound storage to a multi-AZ data store. ElastiCache for Redis with Multi-AZ automatically fails over to a replica in another zone, and an Auto Scaling group spanning multiple zones can launch replacement instances that reconnect to the session store.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create an Amazon EBS snapshot schedule for the attached volumes and restore the snapshots in another Availability Zone after a failure.
Why it's wrong here
Snapshots are point-in-time backups, so any session data written after the last snapshot is lost. Restoring volumes also takes time and requires manual steps, which does not meet the goal of surviving a zone failure without losing session data.
- ✓
Move session data to Amazon ElastiCache for Redis with Multi-AZ enabled, and configure the Auto Scaling group to span multiple Availability Zones.
Why this is correct
Storing session data in ElastiCache for Redis with Multi-AZ provides automatic failover to a replica in another Availability Zone. Spreading the Auto Scaling group across zones lets replacement instances launch in a healthy zone and reconnect to the session store, preserving sessions through a zone failure.
- ✗
Attach an additional EBS volume to each instance and configure RAID 0 across the two volumes for higher durability.
Why it's wrong here
RAID 0 improves I/O performance but reduces durability because a failure of either volume loses the array. Both volumes remain in the same Availability Zone, so this does not protect session data from a zone-level failure.
- ✗
Enable termination protection on the instances and configure the Auto Scaling group to use a single Availability Zone.
Why it's wrong here
Termination protection prevents accidental termination but does not help if the Availability Zone itself fails. Keeping the group in a single zone concentrates risk, so a zone failure would still take down the workload and the session data stored on instance store and the attached EBS volume.
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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 SAA-C03 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 SAA-C03 exam.