Answer: Enable a Multi-AZ deployment for the DB instance.

## Explanation **Correct Answer: A - Enable a Multi-AZ deployment for the DB instance.** **Why this is correct:** 1. **Multi-AZ RDS deployment** provides synchronous replication to a standby replica in a different Availability Zone. 2. The **Recovery Point Objective (RPO)** measures the maximum acceptable amount of data loss measured in time. For Multi-AZ deployments, the RPO is typically **less than 1 second** because: - Data is synchronously replicated to the standby instance - In case of primary instance failure, the standby instance is promoted with minimal data loss - The replication lag is minimal (near-zero) **Why other options are incorrect:** **B. Enable auto scaling for the DB instance in one Availability Zone.** - Auto scaling helps with performance scaling but doesn't provide disaster recovery capabilities - RPO would be much higher (potentially hours or days depending on backup frequency) **C. Configure the DB instance in one Availability Zone, and create multiple read replicas in a separate Availability Zone.** - Read replicas in RDS use **asynchronous replication**, which means there's replication lag - RPO would be measured in seconds or minutes depending on replication lag, not less than 1 second - Read replicas are primarily for read scaling, not for disaster recovery with strict RPO requirements **D. Configure the DB instance in one Availability Zone, and configure AWS Database Migration Service (AWS DMS) change data capture (CDC) tasks.** - DMS CDC replicates data to other targets but with some latency - While DMS can provide near-real-time replication, it's not guaranteed to be less than 1 second RPO - DMS is more for data migration and ongoing replication between different database engines, not for primary disaster recovery with strict RPO requirements **Key AWS Concepts:** - **Multi-AZ RDS**: Provides high availability and failover capability with synchronous replication - **RPO (Recovery Point Objective)**: Maximum acceptable data loss measured in time - **RTO (Recovery Time Objective)**: Maximum acceptable downtime - For strict RPO requirements (<1 second), synchronous replication solutions like Multi-AZ RDS are required

Author: LeetQuiz Editorial Team