Question 520 of 1,546
Reliability and Business ContinuityhardMultiple ChoiceObjective-mapped

Cross-Region Disaster Recovery with ElastiCache Global Datastore

This SOA-C02 practice question tests your understanding of reliability and business continuity. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. A key principle to apply: elastiCache Global Datastore. 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 critical application on a fleet of EC2 instances in an Auto Scaling group behind an Application Load Balancer. The application is deployed in us-east-1 with instances in three Availability Zones. The company's disaster recovery plan requires failover to us-west-2 within 30 minutes with a Recovery Point Objective (RPO) of 15 minutes and a Recovery Time Objective (RTO) of 30 minutes. The application uses an RDS MySQL database and stores session data in ElastiCache Redis. The SysOps administrator has configured an RDS read replica in us-west-2 with cross-Region replication and an ElastiCache cluster in us-west-2. The administrator has also created an AMI of the EC2 instances and copied it to us-west-2. During a disaster simulation, the failover took 45 minutes because the application needed to repopulate the cache. What should the administrator do to meet the RTO? (Select TWO.)

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

Enable ElastiCache Global Datastore for Redis to replicate data across regions.

The 45-minute failover was due to the cold ElastiCache cluster in us-west-2 requiring application-level cache repopulation. To meet the 30-minute RTO, the cache must be warm at failover. Option A enables ElastiCache Global Datastore for Redis, which provides cross-Region replication with sub-minute RPO, keeping the us-west-2 cache synchronized in near real-time, eliminating the need for repopulation after failover. Option D (pre-warming via periodic export/import) is less reliable because it introduces a backup window, does not capture real-time changes, and may not guarantee cache freshness within the 15-minute RPO. Therefore, only Option A fully satisfies both RTO and RPO requirements.

Key principle: ElastiCache Global Datastore

Answer analysis

Option-by-option breakdown

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

  • Enable ElastiCache Global Datastore for Redis to replicate data across regions.

    Why this is correct

    Enables ElastiCache Global Datastore for Redis, providing cross-Region replication with sub-minute RPO, ensuring the cache in us-west-2 is warm and current at failover, meeting the 30-minute RTO.

    Related concept

    ElastiCache Global Datastore

  • Modify the application to store session data in the RDS database instead of ElastiCache.

    Why it's wrong here

    Storing session data in RDS increases database load and latency, and does not address cache warm-up; it also may violate performance SLAs.

  • Increase the size of EC2 instances in us-west-2 to handle the load faster.

    Why it's wrong here

    Increasing EC2 instance size does not reduce cache population time; the bottleneck is the cache initialization, not compute capacity.

  • Pre-warm the ElastiCache cluster in us-west-2 by periodically exporting and importing data from the primary cluster.

    Why this is correct

    Pre-warming via periodic export/import may not capture recent writes, risking data loss exceeding the 15-minute RPO; also the import process adds time, making RTO unachievable.

    Related concept

    ElastiCache Global Datastore

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

  • ElastiCache Global Datastore
  • Recovery Time Objective (RTO)
  • Recovery Point Objective (RPO)
  • Cache warming

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

ElastiCache Global Datastore

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.

Visual reference

Client Server SYN (seq=100) SYN-ACK (seq=200, ack=101) ACK (ack=201) Connection established — data transfer begins

What to study next

Got this wrong? Here's your next step.

Review elastiCache Global Datastore, then practise related SOA-C02 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this SOA-C02 question test?

Reliability and Business Continuity — This question tests Reliability and Business Continuity — ElastiCache Global Datastore.

What is the correct answer to this question?

The correct answer is: Enable ElastiCache Global Datastore for Redis to replicate data across regions. — The 45-minute failover was due to the cold ElastiCache cluster in us-west-2 requiring application-level cache repopulation. To meet the 30-minute RTO, the cache must be warm at failover. Option A enables ElastiCache Global Datastore for Redis, which provides cross-Region replication with sub-minute RPO, keeping the us-west-2 cache synchronized in near real-time, eliminating the need for repopulation after failover. Option D (pre-warming via periodic export/import) is less reliable because it introduces a backup window, does not capture real-time changes, and may not guarantee cache freshness within the 15-minute RPO. Therefore, only Option A fully satisfies both RTO and RPO requirements.

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

Review elastiCache Global Datastore, then practise related SOA-C02 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

ElastiCache Global Datastore

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Last reviewed: Jun 20, 2026

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This SOA-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 SOA-C02 exam.