SOA-C02 Question #134: Real Exam Question with Answer & Explanation

Question

A recent organizational audit uncovered an existing Amazon RDS database that is not currently configured for high availability. Given the critical nature of this database, it must be configured for high availability as soon as possible. How can this requirement be met?

Options

• ASwitch to an active/passive database pair using the create-db-instance-read-replica with the --
• BSpecify high availability when creating a new RDS instance, and live-migrate the data.
• CModify the RDS instance using the console to include the Multi-AZ option.
• DUse the modify-db-instance command with the --na flag.

Explanation

Modifying an existing RDS instance via the console to enable Multi-AZ (option C) is the correct approach because AWS allows you to enable Multi-AZ on a running instance without downtime or data migration - it simply converts the single instance to a primary/standby pair with synchronous replication across Availability Zones.

Why the distractors are wrong:

• A is wrong because create-db-instance-read-replica creates a read replica (asynchronous, for read scaling), not a Multi-AZ standby. Read replicas are not the same as high availability failover pairs.
• B is wrong because you don't need to create a new instance and live-migrate data - AWS supports enabling Multi-AZ on existing instances in-place, making this approach unnecessarily complex and risky.
• D is wrong because there is no --na flag for modify-db-instance; the correct CLI flag would be --multi-az, making this a fabricated distractor.

Memory tip: Think "Modify = Multi-AZ" - whenever AWS asks how to add high availability to an existing RDS instance, the answer is always a simple modification (console or CLI with --multi-az), not a rebuild or replica. If the question said "new instance," the answer would be different - but "existing" points straight to Modify.

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