SAA-C03 Design Secure Architectures Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Multi-AZ RDS primary failure: Fails over automatically to standby

  Why this is correct

  When a primary instance in an Amazon RDS Multi-AZ deployment experiences a failure, AWS automatically detects the issue and initiates a failover. The DNS endpoint for the database is then updated to point to a synchronously replicated standby instance located in a different Availability Zone. This process ensures high availability with minimal downtime and no data loss, as the standby is always up-to-date.

• ✓

  RDS primary failure with read replicas: Requires manual promotion of a read replica

  Why this is correct

  For a single-AZ Amazon RDS instance with read replicas, a primary instance failure necessitates manual intervention to restore full write capabilities. An administrator must explicitly promote one of the existing read replicas to become the new standalone primary database instance. This manual promotion process can lead to some data loss, as read replicas use asynchronous replication and may lag behind the former primary.

• ✓

  Aurora primary failure with replicas: Automatically fails over to an Aurora replica

  Why this is correct

  Amazon Aurora, with its distributed, fault-tolerant storage system, handles primary instance failures very efficiently when Aurora replicas are present. If the primary instance fails, Aurora automatically promotes one of the existing Aurora replicas within the same cluster to become the new primary. This failover is typically completed in less than 30 seconds, leveraging Aurora's shared storage volume and ensuring high availability.

• ✓

  Aurora primary failure without replicas: Recovers in-place

  Why this is correct

  In scenarios where an Amazon Aurora cluster experiences a primary instance failure but has no Aurora replicas configured, the system performs an in-place recovery. Aurora's self-healing, shared storage architecture allows the existing primary instance to be restarted and recovered in the same Availability Zone. While this still provides resilience, the recovery time is generally longer than an automatic failover to an existing replica.

• ✗

  Multi-AZ RDS primary failure: Requires manual promotion of a read replica

  Why it's wrong here

  This statement is incorrect because Amazon RDS Multi-AZ deployments are specifically designed for automatic failover. Upon detecting a primary instance failure, AWS automatically switches the DNS record to a synchronously replicated standby instance in another Availability Zone, eliminating the need for manual promotion or intervention. Manual promotion is characteristic of single-AZ RDS with read replicas, not Multi-AZ.

• ✗

  RDS primary failure with read replicas: Automatically fails over to an Aurora replica

  Why it's wrong here

  This option incorrectly mixes different database technologies and failover mechanisms. Amazon RDS read replicas are used with traditional MySQL, PostgreSQL, etc., and require manual promotion upon primary failure. Furthermore, an "Aurora replica" is a component of an Amazon Aurora cluster, which is a distinct database engine and does not interoperate directly with standard RDS read replicas for failover.