DOP-C02 practice question: Multi-AZ and multi-Region high availability (3 of 3)

Resilient Cloud Solutions A free question from our original DOP-C02 practice exam. Try it, then open the answer to see why each option is right or wrong.

A university runs a student-services application that must stay usable for students in two countries if either Region becomes unavailable. Students write to their own profile records from the Region nearest to them, and both Regions must eventually hold the same data.

Uploaded student documents are stored in Amazon S3 in the primary Region and must be copied to a second Region within a short time, with replication time control enabled so that copies are predictable.

The university wants the solution to use managed AWS features, and it does not want to run its own synchronization service.

Which TWO actions meet these requirements? (Choose two.)

Choose two answers.

A. Keep the application in a single Region with Multi-AZ deployments for the database, and add Route 53 failover to a standby web tier in the second Region that serves read-only pages.
B. Create a DynamoDB global table with replicas in both Regions for the profile records, so that writes in each Region replicate to the other with no custom synchronization.
C. Use a nightly S3 Batch Operations job that copies the documents from the primary Region to the second Region, so the copy happens on a schedule that the operations team controls.
D. Turn on S3 Cross-Region Replication for the document bucket with replication time control enabled, so that new objects are copied to the second Region within the service's replication time target.
E. Store profile records in Amazon Aurora with a single writer in the primary Region, and let students in the second Region reach that writer over a VPC peering connection.

Show the answer and explanation

Answers: B, D

A. Wrong: Multi-AZ protects against an Availability Zone failure, not a Region failure, and the students need writes in both Regions. A read-only standby also fails the requirement for each Region to hold current writes. Learn more: Configuring and managing a Multi-AZ deployment for Amazon RDS (opens in a new tab)
B. Right: Correct. DynamoDB global tables replicate writes between the listed Regions, so students can write to their nearest Region and the data converges. The service is managed, so the university runs no synchronization code. Learn more: Global tables - multi-active, multi-Region replication (opens in a new tab)
C. Wrong: A nightly job leaves up to a day of uploads without a copy, which misses the requirement for a short time. It is also a scheduled copy the team must monitor. Learn more: Replicating objects within and across Regions (opens in a new tab)
D. Right: Correct. Replication time control adds a service-level target for replicating new objects to the destination Region, and the replication rule runs with no custom code. It meets the predictable-copy requirement. Learn more: Replicating objects within and across Regions (opens in a new tab)
E. Wrong: Students in the second Region would still depend on the primary Region for writes, so a regional outage would stop their updates. The design does not meet the requirement that both Regions can accept writes. Learn more: What is VPC peering? (opens in a new tab)

Explanation

DynamoDB global tables let each Region accept writes that replicate to the others, which suits profile records that students update locally. S3 Cross-Region Replication with replication time control copies new documents within a predictable target, with no custom code. Multi-AZ, nightly batch copies and a single writer each fail the requirement for both Regions to take writes or the time target.

DOP-C02 practice question: Multi-AZ and multi-Region high availability (3 of 3)

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