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Difficulty: HardResilient Database Configurations and High Availability

An international logistics provider runs a critical tracking application using Amazon RDS for PostgreSQL in the us-east-1 Region. The company requires a disaster recovery (DR) solution in the us-west-2 Region with a Recovery Point Objective (RPO) of less than 5 minutes and a Recovery Time Objective (RTO) of less than 15 minutes. Additionally, the secondary region must serve read-only reporting workloads during normal operations to offload the primary database. Which combination of actions will meet these requirements? (Select TWO.)

  1. Create a cross-region read replica of the primary database in the us-west-2 Region.Answer
  2. Promote the cross-region read replica to a standalone DB instance in the us-west-2 Region during a disaster recovery event, and update the application connection settings.Answer
  3. C
    Configure an RDS Multi-AZ DB cluster configuration that spans across both the us-east-1 and us-west-2 Regions to enable synchronous replication and automatic failover.
  4. D
    Set up an Amazon Route 53 latency routing policy to automatically promote the secondary database instance and route application write traffic when the primary database is unhealthy.
  5. E
    Configure AWS Backup to take database snapshots every 4 hours, copy them to the us-west-2 Region, and restore the database from the copied snapshots during a failover event.

Answer

To meet the requirements, the company should create a cross-region read replica in the secondary region to handle reporting workloads and maintain low replication lag, and then promote that replica to a standalone DB instance during a DR event.
The correct actions are to create a cross-region read replica in the secondary region and to promote this replica to a standalone instance during a failover. The cross-region read replica satisfies the RPO of less than 5 minutes due to continuous asynchronous replication and allows read-only reporting queries to run in the secondary region. Promoting the read replica takes only a few minutes, which satisfies the 15-minute RTO.

Step-by-Step Solution

1
Select a replication method that meets the RPO and read workload requirements.
Creating an Amazon RDS cross-region read replica provides near-continuous asynchronous replication (meeting the 5-minute RPO) and can serve read-only reporting traffic during normal operations.
Asynchronous replication to a read replica offloads reads and replicates changes without synchronous write latency across regions.
2
Select a failover method that meets the 15-minute RTO requirement.
Promoting the read replica to a standalone instance takes only a few minutes.
Promoting an existing read replica is significantly faster than restoring from backups or setting up new instances, keeping RTO well under the 15-minute threshold.
3
Identify and eliminate options that are technically impossible or violate constraints.
Eliminated Multi-AZ spanning regions (not supported), Route 53 database promotion (DNS only), and 4-hour backup restore (violates RPO).
Multi-AZ is single-region, Route 53 cannot perform database operations, and snapshot restores from 4-hour intervals violate the RPO constraint.

Key Concept

Cross-Region Disaster Recovery using RDS Read Replicas
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Topics

Resilient Database Configurations and High Availability

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