RDS PostgreSQL Multi-AZ High Availability Deployment
A company is deploying a new application with a PostgreSQL database on Amazon RDS. The database must be highly available across two Availability Zones. Which deployment option meets this requirement?
Quick Answer
The correct answer is Multi-AZ RDS instance because this deployment option automatically provisions and maintains a synchronous standby replica in a different Availability Zone, ensuring automatic failover with zero data loss for PostgreSQL. This architecture meets the high availability requirement by replicating data synchronously across two AZs, so if the primary instance fails, RDS automatically flips the DNS record to the standby, minimizing downtime. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of the distinction between Multi-AZ for high availability and read replicas for scaling—a common trap is confusing read replicas (which are asynchronous and require manual promotion) with Multi-AZ’s synchronous failover. Remember the memory tip: “Multi-AZ for uptime, read replicas for read time.”
⚠ Common exam trap
It's easy for candidates to confuse read replicas with Multi-AZ deployments, assuming a read replica in another AZ provides high availability, but it lacks automatic failover and synchronous replication required for true HA.
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
✓
Multi-AZ RDS instance.
A Multi-AZ RDS instance automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover for high availability. This ensures the database remains accessible even if the primary AZ fails, meeting the requirement for cross-AZ high availability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
RDS with a read replica in another AZ.
Why it's wrong here
Read replicas do not provide automatic failover.
- ✓
Multi-AZ RDS instance.
Why this is correct
Provides automatic failover to a standby in another AZ.
- ✗
Single-AZ RDS instance.
Why it's wrong here
No failover capability.
- ✗
Amazon Aurora Global Database.
Why it's wrong here
Amazon Aurora Global Database replicates data across multiple AWS Regions, not across two Availability Zones within a single region, so it does not satisfy the requirement for zone-level high availability. This option is tempting because its name implies broad geographic resilience, and it would be correct if the scenario demanded cross-region disaster recovery rather than intra-region zone redundancy.
Go deeper
Related to this question
About these practice questions
This DBS-C01 question is part of Courseiva's 1,663-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
2 more ways this is tested on DBS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is deploying a new web application that uses Amazon RDS for PostgreSQL. The database must be highly available with automatic failover across two Availability Zones. Which deployment option meets this requirement?
easy- A.Deploy RDS PostgreSQL in a cross-region replication setup.
- ✓ B.Deploy RDS PostgreSQL with Multi-AZ configuration.
- C.Deploy RDS PostgreSQL in a single Availability Zone.
- D.Deploy RDS PostgreSQL with a read replica in another AZ.
Why B: Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone. If the primary DB instance fails, Amazon RDS automatically fails over to the standby, providing high availability with automatic failover across two AZs. This meets the requirement without manual intervention or application changes.
Variation 2. A company is deploying a new application that uses Amazon RDS for PostgreSQL. The database must be highly available and fault-tolerant. Which deployment option meets these requirements?
easy- A.Deploy the RDS instance in a single Availability Zone
- B.Deploy the RDS instance across multiple AWS Regions
- ✓ C.Deploy the RDS instance with Multi-AZ configuration
- D.Deploy the RDS instance with multiple read replicas
Why C: Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover in the event of an AZ outage or primary instance failure. This configuration meets the requirements for high availability and fault tolerance by ensuring the database remains accessible with minimal downtime, as the standby replica is kept in sync synchronously and DNS is updated to point to the standby upon failover.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.