What would happen to RDS if the primary database instance fails?

An accounting application uses an RDS database configured with Multi-AZ deployments to improve availability .

What would happen to RDS if the primary database instance fails?
A . The IP address of the primary DB instance is switched to the standby DB instance.
B . The primary database instance will reboot.
C . A new database instance is created in the standby Availability Zone.
D . The canonical name record (CNAME) is switched from the primary to standby instance.

View Answer

Answer: D

Explanation:

In Amazon RDS, failover is automatically handled so that you can resume database operations as quickly as possible without administrative intervention in the event that your primary database instance goes down. When failing over, Amazon RDS simply flips the canonical name record (CNAME) for your DB instance to point at the standby, which is in turn promoted to become the new primary.

The option that says: The IP address of the primary DB instance is switched to the standby DB instance is incorrect since IP addresses are per subnet, and subnets cannot span multiple AZs.

The option that says: The primary database instance will reboot is incorrect since in the event of a failure, there is no database to reboot with.

The option that says: A new database instance is created in the standby Availability Zone is incorrect

since with multi-AZ enabled, you already have a standby database in another AZ.

References:

https://aws.amazon.com/rds/details/multi-az/

https://aws.amazon.com/rds/faqs/

Amazon RDS Overview:

https://youtu.be/aZmpLl8K1UU

Check out this Amazon RDS Cheat Sheet:

https://tutorialsdojo.com/amazon-relational-database-service-amazon-rds/