AWS Certified Cloud Practitioner

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.