DBS-C01 Workload-Specific Database Design Practice Question
A company is using Amazon ElastiCache for Redis as a caching layer for frequently accessed data. The application needs to support caching of session data that must be highly available across multiple Availability Zones. Which ElastiCache configuration should be used?
⚠ Common exam trap
It's easy for candidates to confuse cluster mode enabled/disabled with multi-AZ support, mistakenly thinking that cluster mode disabled cannot place replicas in different AZs, when in fact both modes support multi-AZ replication, but the question's requirement for 'highly available across multiple Availability Zones' and the specific wording of the correct answer point to cluster mode enabled as the intended solution for a Redis cluster that can scale and survive AZ failures.
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
✓
Deploy a Redis cluster with cluster mode enabled and replica nodes in a different Availability Zone.
Deploying a Redis cluster with cluster mode enabled and replica nodes in a different Availability Zone provides both high availability and automatic failover for session data. ElastiCache for Redis with cluster mode enabled supports sharding and replication, allowing replica nodes to be placed in a separate AZ to survive an AZ failure. This configuration ensures session data remains accessible even if the primary node or an entire AZ becomes unavailable, meeting the requirement for multi-AZ high availability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploy a single Redis node in one Availability Zone.
Why it's wrong here
A single node has no high availability; if it fails, data is lost.
- ✗
Deploy a Redis cluster with cluster mode disabled.
Why it's wrong here
Without cluster mode, there is only one shard; replicas can be added but not for automatic failover in all configurations.
- ✗
Deploy a Memcached cluster with multiple nodes.
Why it's wrong here
Memcached does not support replication; high availability is limited.
- ✓
Deploy a Redis cluster with cluster mode enabled and replica nodes in a different Availability Zone.
Why this is correct
Cluster mode with replicas across AZs provides high availability and automatic failover.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.