SOA-C02 Reliability and Business Continuity Practice Question

A company has a production RDS for PostgreSQL instance with Multi-AZ enabled. During a recent failover test, the application experienced a 5-minute downtime. The company requires that failover be completed within 2 minutes. Which action should be taken to meet this requirement?

⚠ Common exam trap

Watch out — candidates often assume increasing instance size or enabling backups improves failover speed, but the real bottleneck is connection management and DNS propagation, which RDS Proxy addresses directly.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Configure an RDS Proxy in front of the database.

RDS Proxy reduces failover time by maintaining database connections and connection pooling, allowing the application to reconnect quickly without waiting for DNS propagation or new connection setup. In a Multi-AZ failover, RDS Proxy can typically complete failover in under 60 seconds, meeting the 2-minute requirement by minimizing connection disruption.

Answer analysis

Option-by-option breakdown

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

✗
Migrate the database to Amazon Aurora with Multi-AZ.
Why it's wrong here
Migrating to Aurora with Multi-AZ is a significant architectural undertaking that does not address the root cause of connection failures during failover. While Aurora does provide faster failover at the storage layer and uses a quorum-based system, it still terminates existing client connections when a failover occurs, forcing applications to reconnect and handle the disruption manually. RDS Proxy is a less invasive, universally compatible solution that maintains connection state across failovers and is sufficient for the stated requirement.
✗
Enable automated backups with a short retention period.
Why it's wrong here
Enabling automated backups with a short retention period only protects against data loss and enables point-in-time recovery; it has no bearing on the failover mechanism itself. Backups are taken from a separate snapshot storage layer and do not affect how quickly RDS detects an impairment, promotes the standby, or re-establishes connectivity. Consequently, short backups neither reduce failover time nor prevent the application from experiencing connection drops.
✗
Increase the DB instance class to a larger size.
Why it's wrong here
Increasing the DB instance class provides more computational and memory resources, which can improve throughput but does not influence the failover path or connection lifecycle. Failover behavior is governed by RDS's internal health checking, replication status, and DNS updates—none of which are impacted by instance size. In fact, a larger instance might be more wasteful if the current instance is not resource-constrained, and the failover time is typically dominated by setup and promotion steps that are identical across classes.
✓
Configure an RDS Proxy in front of the database.
Why this is correct
Configuring an RDS Proxy in front of the database is the correct, targeted fix because the proxy maintains persistent outbound connections to the DB endpoints and pools inbound client connections. During a failover, RDS Proxy automatically establishes connections to the new primary and keeps the client-side connections open, making the failover appear essentially transparent to the application. This eliminates the need for clients to implement complex reconnect logic and reduces the overall failover time by avoiding a cold-start connection establishment storm.

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SOA-C02 Reliability and Business Continuity Practice Question

Why each option matters

Option-by-option breakdown

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