Question 176 of 1,616
Development with AWS ServicesmediumMultiple ChoiceObjective-mapped

Why S3 for Session State Causes Logouts: Consistency and Latency Issues

This DVA-C02 practice question tests your understanding of development with aws services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: session State Storage. 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 company runs a web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application stores session state in an S3 bucket. Users report that after logging in, they are sometimes redirected to the login page again on subsequent requests. What is the MOST likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

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

S3 is not a suitable store for session state due to its eventual consistency and higher latency.

Amazon S3 now provides strong read-after-write consistency, so eventual consistency is not the cause. However, S3's higher latency compared to in-memory stores like ElastiCache or DynamoDB makes it unsuitable for session management, which requires fast, frequent reads and writes. The higher latency can cause delays in session retrieval, leading to timeouts and the login page being displayed again.

Key principle: Session State Storage

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • S3 is not a suitable store for session state due to its eventual consistency and higher latency.

    Why this is correct

    Although S3 now provides strong consistency, its higher latency can cause session retrieval delays, leading to login page redirection. This makes it unsuitable for session state, so this option is correct.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Session State Storage

  • The EC2 instances do not have internet access to reach S3.

    Why it's wrong here

    If EC2 instances lacked internet access, they would be unable to reach S3 entirely, causing persistent failures, not intermittent redirection.

  • The ALB does not have sticky sessions enabled.

    Why it's wrong here

    Since session state is stored in S3 (a shared store), sticky sessions are not required. The ALB's sticky session setting does not affect session persistence in this setup.

  • The application is not scaling properly, causing session loss.

    Why it's wrong here

    Improper scaling (e.g., terminating instances with local session data) would cause session loss only if session state were stored locally. Here, it's stored externally in S3, so scaling does not directly cause the issue.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Candidates may incorrectly attribute the problem to S3's eventual consistency, which was fixed. The real issue is S3's higher latency relative to in-memory services, making it a poor choice for session state.

Detailed technical explanation

How to think about this question

S3's eventual consistency model means that after an overwrite (e.g., updating session data), a subsequent GET request might return the previous version or a 404 if the object was deleted. For session state, which requires strong consistency (every read must reflect the latest write), S3 is inappropriate. In contrast, Amazon DynamoDB offers strongly consistent reads (at additional cost) and is a recommended session store, while ElastiCache provides sub-millisecond in-memory performance with immediate consistency.

KKey Concepts to Remember

  • Session State Storage

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

Session State Storage

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.

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

What to study next

Got this wrong? Here's your next step.

Review session State Storage, then practise related DVA-C02 questions on the same topic to reinforce the concept.

Related practice questions

Related DVA-C02 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Practice this exam

Start a free DVA-C02 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

FAQ

Questions learners often ask

What does this DVA-C02 question test?

Development with AWS Services — This question tests Development with AWS Services — Session State Storage.

What is the correct answer to this question?

The correct answer is: S3 is not a suitable store for session state due to its eventual consistency and higher latency. — Amazon S3 now provides strong read-after-write consistency, so eventual consistency is not the cause. However, S3's higher latency compared to in-memory stores like ElastiCache or DynamoDB makes it unsuitable for session management, which requires fast, frequent reads and writes. The higher latency can cause delays in session retrieval, leading to timeouts and the login page being displayed again.

What should I do if I get this DVA-C02 question wrong?

Review session State Storage, then practise related DVA-C02 questions on the same topic to reinforce the concept.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Session State Storage

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

More DVA-C02 practice questions

Last reviewed: Jul 4, 2026

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

Sign in to join the discussion.

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.