Question 619 of 1,733
MigrationhardMultiple ChoiceObjective-mapped

PAS-C01 Sticky sessions Practice Question

This PAS-C01 practice question tests your understanding of migration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: sticky sessions. 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 is migrating a multi-tier web application to AWS. The web tier uses sticky sessions. The application tier uses a shared session store. Which architecture ensures high availability and scalability?

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

Use an Application Load Balancer with sticky sessions and Amazon ElastiCache for session storage.

Option C is correct because an Application Load Balancer (ALB) supports sticky sessions, and Amazon ElastiCache provides a scalable, low-latency, distributed session store that is shared across instances, ensuring high availability and scalability. Option A is incorrect because storing sessions on each EC2 instance does not provide a shared session store; if an instance fails, its sessions are lost. Option B is incorrect because while the Classic Load Balancer supports sticky sessions and RDS can be used as a session store, RDS is not optimized for high-throughput session data and the Classic Load Balancer lacks advanced features like path-based routing and is considered legacy. Option D is incorrect because Amazon CloudFront is a content delivery network (CDN) and is not designed for session storage; S3 is object storage with higher latency, making it unsuitable for real-time session data.

Key principle: Sticky sessions

Answer analysis

Option-by-option breakdown

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

  • Use an Application Load Balancer with sticky sessions enabled, and store sessions on each EC2 instance.

    Why it's wrong here

    Incorrect. Storing sessions on each EC2 instance lacks a shared session store, so if an instance fails, sessions are lost. This does not provide high availability.

  • Use a Classic Load Balancer with sticky sessions and store sessions in RDS.

    Why it's wrong here

    Incorrect. A Classic Load Balancer supports sticky sessions but lacks advanced features. Storing sessions in RDS can cause database bottlenecks and latency, not optimal for a distributed session store.

  • Use an Application Load Balancer with sticky sessions and Amazon ElastiCache for session storage.

    Why this is correct

    Correct. The Application Load Balancer provides sticky sessions. Amazon ElastiCache is a distributed in-memory cache ideal for a shared session store, supporting high availability and scalability.

    Related concept

    Sticky sessions

  • Use Amazon CloudFront with origin failover and store sessions in S3.

    Why it's wrong here

    Incorrect. CloudFront is a content delivery network, not a load balancer. S3 is object storage with eventual consistency, not suitable for fast session storage.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • Sticky sessions
  • Shared session store
  • Application Load Balancer (ALB)
  • Amazon ElastiCache

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

Sticky sessions

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 sticky sessions, then practise related PAS-C01 questions on the same topic to reinforce the concept.

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

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FAQ

Questions learners often ask

What does this PAS-C01 question test?

Migration — This question tests Migration — Sticky sessions.

What is the correct answer to this question?

The correct answer is: Use an Application Load Balancer with sticky sessions and Amazon ElastiCache for session storage. — Option C is correct because an Application Load Balancer (ALB) supports sticky sessions, and Amazon ElastiCache provides a scalable, low-latency, distributed session store that is shared across instances, ensuring high availability and scalability. Option A is incorrect because storing sessions on each EC2 instance does not provide a shared session store; if an instance fails, its sessions are lost. Option B is incorrect because while the Classic Load Balancer supports sticky sessions and RDS can be used as a session store, RDS is not optimized for high-throughput session data and the Classic Load Balancer lacks advanced features like path-based routing and is considered legacy. Option D is incorrect because Amazon CloudFront is a content delivery network (CDN) and is not designed for session storage; S3 is object storage with higher latency, making it unsuitable for real-time session data.

What should I do if I get this PAS-C01 question wrong?

Review sticky sessions, then practise related PAS-C01 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

Sticky sessions

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Last reviewed: Jun 20, 2026

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This PAS-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 PAS-C01 exam.