Explanation
Multi-AZ (Option B) and Read Replicas (Option C) are the correct answers for increasing database availability.
Why Multi-AZ and Read Replicas?
Multi-AZ Deployments:
- Provides high availability by automatically maintaining a synchronous standby replica in a different Availability Zone
- Automatic failover capability in case of primary database failure
- Protects against unplanned outages and infrastructure failures
- Ensures data durability and continuous availability
Read Replicas:
- Provide read scalability by offloading read traffic from the primary database
- Can be promoted to standalone instances if needed
- Work in conjunction with Multi-AZ deployments for comprehensive availability
Why Not the Other Options?
VPC Peering (Option A):
- This is a networking feature that allows connectivity between VPCs
- Does not directly provide database availability features
- Primarily for network connectivity, not database replication
Multi-Region (Option D):
- While this can provide geographic redundancy, it's not specifically mentioned in the AWS documentation as the primary method for database availability
- Multi-AZ within the same region is typically the first choice for high availability
AWS Documentation Reference
As mentioned in the AWS documentation: "If you are looking to use replication to increase database availability while protecting your latest database updates against unplanned outages, consider running your DB instance as a Multi-AZ deployment. You can use Multi-AZ deployments and Read Replicas in conjunction to enjoy the complementary benefits of each."
This combination provides both high availability (Multi-AZ) and read scaling capabilities (Read Replicas) for comprehensive database performance and reliability.
