Answer: Modify the DB instance from a Single-AZ DB instance to a Multi-AZ deployment., Create a read replica of the DB instance in a different Availability Zone. Point all requests for reports to the read replica.

## Explanation **Correct Answers: A and C** ### Why A (Multi-AZ deployment) is correct: - **High Availability Requirement**: The company needs high availability and automatic recovery for the DB instance. Multi-AZ deployment provides synchronous replication to a standby instance in a different Availability Zone. - **Automatic Failover**: In case of primary instance failure, Amazon RDS automatically fails over to the standby instance, minimizing downtime. - **Automatic Recovery**: Multi-AZ deployments include automated backups, software patching, and automatic failure detection and recovery. ### Why C (Read replica for reporting) is correct: - **Performance Improvement for Reports**: The report process causes transactions to take longer than usual. By creating a read replica and pointing report requests to it: - Reports run on the read replica, not the primary instance - Transaction processing on the primary instance is not impacted by heavy reporting queries - Read replicas provide read scaling capabilities - Reports can run without affecting customer transaction processing ### Why other options are incorrect: **B (Snapshot and restore to another AZ)**: - This creates a separate database instance, not a synchronized standby - No automatic failover capability - Manual process that doesn't provide high availability - Data would be stale (point-in-time snapshot) **D (Migrate to RDS Custom)**: - RDS Custom is for databases requiring OS and database engine access - Doesn't address the high availability or reporting performance requirements - More complex and expensive solution **E (RDS Proxy to limit reporting requests)**: - RDS Proxy manages database connections but doesn't solve the performance issue - Limiting reports to maintenance window doesn't improve performance, just delays the problem - Doesn't provide high availability ### Key AWS Concepts: 1. **Multi-AZ Deployment**: Provides high availability with automatic failover to a standby replica in another Availability Zone. 2. **Read Replicas**: Provide read scaling by offloading read traffic from the primary database instance. 3. **Use Case Fit**: The combination of Multi-AZ (for HA) and read replica (for reporting performance) perfectly addresses both requirements. **Best Practice**: For production databases requiring high availability, always use Multi-AZ deployment. For read-heavy workloads or reporting, use read replicas to offload read traffic from the primary instance.