Examkin

Question

Difficulty: MediumResilient Database Configurations and High Availability

An e-commerce company is migrating its ordering database to AWS and requires a resilient design using Amazon RDS for PostgreSQL. The database must survive an Availability Zone (AZ) outage with a Recovery Time Objective (RTO) of under 60 seconds, and it must support horizontal read scaling for search queries within the same AWS Region. Which configuration meets these requirements with the lowest operational overhead?

  1. A
    Deploy a Single-AZ DB instance and create an asynchronous Read Replica in a different Availability Zone, configuring the application to promote the replica during an outage.
  2. Deploy a Multi-AZ DB cluster with one primary and two readable standby DB instances.Answer
  3. C
    Deploy a Multi-AZ DB instance deployment, and configure Route 53 latency-based routing to load balance write operations across a replica in another AWS Region.
  4. D
    Deploy a Single-AZ DB instance, and configure a warm standby DB instance in a separate Availability Zone that is synchronized daily using Amazon RDS snapshots.

Answer

Deploy a Multi-AZ DB cluster with one primary and two readable standby DB instances.
The correct configuration is a Multi-AZ DB cluster with one primary and two readable standby DB instances. This option provides high availability by automatically failing over in less than 35 seconds, which satisfies the RTO requirement. It also natively supports horizontal read scaling because both standby DB instances can accept read requests through the reader endpoint.

Step-by-Step Solution

1
Analyze high availability and read scaling requirements.
The configuration must support a failover time (RTO) of less than 60 seconds during an Availability Zone outage and offer read scalability within the same region.
This establishes the constraints needed to rule out configurations that do not support automated failover or read endpoint integration.
2
Compare Multi-AZ DB instances against Multi-AZ DB clusters.
A standard Multi-AZ DB instance provides failover but the standby instance cannot serve read traffic. A Multi-AZ DB cluster provides automated failover and allows its two standby instances to process read queries.
Choosing the cluster configuration satisfies both failover and read scaling within a single native RDS architecture, minimizing operational complexity.
3
Verify compliance with the RTO constraint.
Amazon RDS Multi-AZ DB clusters fail over in under 35 seconds, which is well within the 60-second RTO.
This confirms the proposed architecture meets all defined service level requirements.

Key Concept

Amazon RDS Multi-AZ DB clusters combine high availability (automated failover) and read scalability by deploying a primary and two readable standby instances across three Availability Zones.
Estimated Time:2m 0s
Rate this question

Topics

Resilient Database Configurations and High Availability

More questions from this topic