Answer: Set up an Aurora global database for the DB cluster. Specify a minimum of one DB instance in the secondary Region.

## Explanation **Option D is the correct answer** because it provides the most cost-effective solution for disaster recovery with Aurora MySQL. ### Analysis of Each Option: **Option A: MySQL binary log replication** - This requires manual setup and management of binary log replication - You still need to provision a DB instance in the secondary Region (which incurs costs) - More complex to manage and maintain compared to native AWS solutions - Not the most cost-effective option **Option B: Aurora global database with removal of secondary instance** - Aurora global database requires at least one DB instance in the secondary Region to function - Removing the DB instance would break the replication functionality - Aurora global database needs active instances in secondary Regions to maintain replication - This option is not feasible **Option C: AWS DMS with instance removal** - AWS DMS requires continuous replication tasks which incur additional costs - Removing the DB instance in the secondary Region would mean there's no database to replicate to - DMS has ongoing costs for replication tasks - Not cost-effective compared to native Aurora solutions **Option D: Aurora global database with minimum one DB instance** - **Most cost-effective**: Aurora global database provides built-in cross-region replication with minimal overhead - **Native solution**: No additional services or complex setup required - **Automatic failover**: Built-in failover capabilities to secondary Region - **Low latency**: Uses dedicated infrastructure for replication - **Cost-efficient**: Only pay for the DB instance in the secondary Region, no additional replication service costs - **Scalable**: Can add more instances in secondary Region if needed - **Managed**: AWS handles the replication infrastructure ### Why Option D is Best: 1. **Aurora global database** is specifically designed for cross-region disaster recovery scenarios 2. **Minimal instance configuration** (one instance) keeps costs low while maintaining DR readiness 3. **No additional service costs** - unlike DMS which has ongoing replication task costs 4. **Simplified management** - AWS manages the replication infrastructure 5. **Automatic and continuous** - data is replicated with typically less than 1 second latency This solution meets the requirements for a high-volume SaaS platform by providing reliable cross-region replication while minimizing costs through Aurora's native global database feature.

Author: LeetQuiz Editorial Team