DVA-C02 Development with AWS Services Practice Question
A developer needs to store session state data for a web application running on multiple EC2 instances. The data must be highly available and durable. Which AWS service should be used?
⚠ Common exam trap
Many candidates confuse Amazon ElastiCache with Amazon DynamoDB or Amazon S3 for session storage, but the question specifically requires a highly available and durable in-memory solution, and ElastiCache is the only option that provides low-latency, shared session state across multiple EC2 instances with built-in replication and failover.
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
✓
Amazon ElastiCache
Amazon ElastiCache is the correct choice because it provides a managed, in-memory caching service that is ideal for storing session state data with high availability and durability. By using ElastiCache for Redis or Memcached, session data is stored outside of individual EC2 instances, ensuring that if an instance fails, the session state is preserved and can be accessed by other instances in the application tier. ElastiCache supports replication and automatic failover, meeting the requirements for high availability and durability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Amazon ElastiCache
Why this is correct
Amazon ElastiCache provides managed in-memory data stores, such as Redis or Memcached, which offer extremely low-latency access and high throughput. This makes it an ideal choice for storing frequently accessed, transient session state data for web applications. By centralizing session state in ElastiCache, application servers can remain stateless, allowing for seamless horizontal scaling and high availability across multiple instances without losing user sessions.
- ✗
Amazon S3
Why it's wrong here
Amazon S3 is an object storage service designed for high durability and availability of static assets, backups, and large data lakes, not for low-latency, high-frequency read/write operations required by dynamic session state. While highly scalable, its typical access latency, measured in milliseconds, is too high for interactive web application session management, which demands sub-millisecond responses to maintain a smooth user experience. It lacks the necessary performance characteristics for real-time session data.
- ✗
Amazon EBS
Why it's wrong here
Amazon EBS (Elastic Block Store) provides persistent block storage volumes that can be attached to a single EC2 instance, functioning like a network-attached hard drive. It is designed for file systems, databases, or operating system boot volumes, requiring a direct, exclusive attachment to one instance at a time. This architecture makes EBS unsuitable for shared session state across multiple web servers in a horizontally scaled application, as it cannot be simultaneously accessed by different instances.
- ✗
Amazon CloudFront
Why it's wrong here
Amazon CloudFront is a global content delivery network (CDN) service that caches static and dynamic web content at edge locations worldwide to reduce latency for end-users. Its primary function is to accelerate content delivery and improve application performance by serving content closer to the user, not to store or manage application-specific session state data. CloudFront operates at the network edge and does not provide a persistent, centralized data store for application backend logic or user session information.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-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 DVA-C02 exam.