Question

Difficulty: EasyResilient Database Configurations and High Availability

A solutions architect is designing the database tier for a critical web application. The application will use an Amazon RDS for PostgreSQL DB instance and requires high availability with automatic failover within a single AWS Region.

Which two options should the solutions architect implement to meet these requirements? (Select two.)

  1. Deploy the RDS DB instance in a Multi-AZ configuration to enable synchronous replication to a standby instance in a different Availability Zone.Answer
  2. Configure the application to connect using the primary DB instance DNS endpoint, which AWS automatically updates to point to the standby instance during failover.Answer
  3. C
    Configure an RDS Read Replica in a different Availability Zone and update the application connection string to write to the replica if the primary instance fails.
  4. D
    Set up a Warm Standby DB instance in another AWS Region and use Route 53 latency-based routing to automatically redirect write traffic if the primary region goes offline.
  5. E
    Deploy the database in a Pilot Light configuration with a second scaled-down standby DB instance in another Availability Zone that is manually turned on during a failure.

Answer

Deploy the RDS DB instance in a Multi-AZ configuration to enable synchronous replication, and configure the application to connect using the primary DB instance DNS endpoint.
The correct options are deploying the RDS DB instance in a Multi-AZ configuration and configuring the application to connect using the primary DB instance DNS endpoint. Multi-AZ configurations provide synchronous replication and automatic failover to a standby instance in another Availability Zone. During failover, AWS automatically updates the DNS record of the DB instance endpoint, allowing the application to connect to the new primary instance without code or configuration changes.

Step-by-Step Solution

1
Identify the high availability (HA) and automatic failover requirements for Amazon RDS.
Amazon RDS Multi-AZ deployments satisfy this by creating a synchronous standby replica in another Availability Zone.
Multi-AZ provides automatic failover, synchronous data replication, and high availability within a single AWS Region.
2
Determine how the application should handle connection redirection during a database failover.
Use the standard RDS DB instance DNS endpoint, which AWS automatically updates to point to the newly promoted primary standby.
This avoids having to modify the application's connection string when a failover occurs, keeping failover seamless.

Key Concept

Amazon RDS Multi-AZ High Availability and Failover Mechanics
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