- A
Amazon ElastiCache with Redis
ElastiCache with Redis is ideal for session state storage. It provides in-memory caching with low latency, supports TTL for automatic expiration, and can be accessed from any Lambda function via a VPC. It is a common pattern for serverless session management.
- B
Amazon DynamoDB with TTL
Why wrong: DynamoDB can be used to store session data with TTL, but it is not as performant as ElastiCache for frequent small reads and writes. It also incurs read/write costs and may have higher latency due to network calls and eventual consistency. ElastiCache is preferred for session caching.
- C
Amazon S3
Why wrong: Amazon S3 is object storage and not designed for low-latency, small-footprint session data. Retrieving and writing session data to S3 would be slower and more expensive due to PUT/GET operations and potential consistency delays.
- D
Local storage (Lambda ephemeral storage /tmp)
Why wrong: Lambda's /tmp directory is ephemeral and not shared between different function invocations or across different functions. It cannot be used to share session data across invocations.
DVA-C02 Development with AWS Services Practice Question
This DVA-C02 practice question tests your understanding of development with aws services. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is building a serverless application that needs to store user session data. The data is small (a few KB per user) and must be accessible across multiple invocations of the same Lambda function and across different Lambda functions. The session data should persist for the duration of the user session (up to 1 hour). Which storage solution should the developer use?
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 with Redis
Amazon ElastiCache with Redis is the correct choice because it provides an in-memory data store with sub-millisecond latency, making it ideal for storing small, ephemeral session data that needs to be shared across multiple Lambda invocations and functions. Redis supports key-value storage with configurable Time-to-Live (TTL) for automatic expiration, aligning perfectly with the 1-hour session duration requirement. Unlike other options, ElastiCache is designed for low-latency, cross-function access without the overhead of database writes or file system limitations.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 with Redis
Why this is correct
ElastiCache with Redis is ideal for session state storage. It provides in-memory caching with low latency, supports TTL for automatic expiration, and can be accessed from any Lambda function via a VPC. It is a common pattern for serverless session management.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon DynamoDB with TTL
Why it's wrong here
DynamoDB can be used to store session data with TTL, but it is not as performant as ElastiCache for frequent small reads and writes. It also incurs read/write costs and may have higher latency due to network calls and eventual consistency. ElastiCache is preferred for session caching.
- ✗
Amazon S3
Why it's wrong here
Amazon S3 is object storage and not designed for low-latency, small-footprint session data. Retrieving and writing session data to S3 would be slower and more expensive due to PUT/GET operations and potential consistency delays.
- ✗
Local storage (Lambda ephemeral storage /tmp)
Why it's wrong here
Lambda's /tmp directory is ephemeral and not shared between different function invocations or across different functions. It cannot be used to share session data across invocations.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose DynamoDB with TTL because it is a serverless, managed service with automatic expiration, but they overlook the fact that session data requires ultra-low latency and high throughput that only an in-memory cache like Redis can provide, and DynamoDB's per-request latency and cost model are suboptimal for this use case.
Detailed technical explanation
How to think about this question
Under the hood, ElastiCache for Redis uses a distributed in-memory architecture where data is stored in RAM across cluster nodes, enabling sub-millisecond read/write operations via the Redis protocol (RESP). The TTL feature is implemented using Redis's EXPIRE command, which sets a key-level expiration that is automatically evicted after the specified time (e.g., 3600 seconds for 1 hour). In a real-world scenario, a serverless application handling user sessions across multiple microservices (e.g., authentication, cart, and profile Lambdas) would use ElastiCache as a centralized session store, ensuring consistent state without the cold-start penalty of DynamoDB or the latency of S3.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Amazon ElastiCache with Redis — Amazon ElastiCache with Redis is the correct choice because it provides an in-memory data store with sub-millisecond latency, making it ideal for storing small, ephemeral session data that needs to be shared across multiple Lambda invocations and functions. Redis supports key-value storage with configurable Time-to-Live (TTL) for automatic expiration, aligning perfectly with the 1-hour session duration requirement. Unlike other options, ElastiCache is designed for low-latency, cross-function access without the overhead of database writes or file system limitations.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 11, 2026
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.
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