Examkin

Question

Difficulty: MediumDisaster Recovery Strategies

A company hosts a web application on Amazon EC2 instances with an Amazon RDS for MySQL DB instance. A SysOps Administrator must establish a cross-region disaster recovery (DR) strategy with a Recovery Point Objective (RPO) of 1 hour and a Recovery Time Objective (RTO) of 30 minutes. The solution must minimize ongoing running costs in the recovery region. Which disaster recovery strategy should the SysOps Administrator implement to meet these requirements?

  1. Configure a cross-region Amazon RDS read replica in the recovery region. Maintain the application tier infrastructure as an AWS CloudFormation template. In the event of a disaster, deploy the CloudFormation stack to launch the EC2 instances, promote the read replica to a standalone DB instance, and update Amazon Route 53 routing to point to the new resources.Answer
  2. B
    Configure the Amazon RDS DB instance with Multi-AZ replication targeting the recovery region. Launch a minimum capacity Auto Scaling group of EC2 instances in the recovery region, and configure Route 53 to route all database queries directly to the RDS standby replica endpoint during a failover.
  3. C
    Deploy a duplicate active-active environment in the recovery region with running EC2 instances and a read replica of the RDS DB instance. Configure an Amazon Route 53 active-active weighted routing policy to distribute traffic equally between both regions, ensuring automatic DNS failover without manual database promotion.
  4. D
    Implement a Pilot Light strategy. Configure AWS Backup to copy database snapshots to the recovery region every hour. Set up Amazon S3 Cross-Region Replication to copy application files to the destination bucket in the recovery region, without enabling versioning on the source bucket to minimize storage costs.

Answer

Configure a cross-region Amazon RDS read replica in the recovery region. Maintain the application tier infrastructure as an AWS CloudFormation template. In the event of a disaster, deploy the CloudFormation stack to launch the EC2 instances, promote the read replica to a standalone DB instance, and update Amazon Route 53 routing to point to the new resources.
The correct strategy is a Pilot Light configuration. An RDS cross-region read replica keeps the data synchronized asynchronously, meeting the 1-hour RPO target. Keeping the application resources in an AWS CloudFormation template avoids ongoing EC2 costs in the recovery region, and deploying them takes only minutes, easily meeting the 30-minute RTO constraint.

Step-by-Step Solution

1
Analyze the RTO, RPO, and cost constraints.
An RPO of 1 hour requires continuous data replication, while an RTO of 30 minutes requires automated template-based provisioning or pre-warmed servers. The cost constraint dictates minimizing running compute resources in the recovery region.
This rules out full active-active strategies due to high cost, and rules out backup-and-restore strategies due to the time required to restore database instances from snapshots exceeding 30 minutes.
2
Determine the database replication mechanism for cross-region disaster recovery.
Amazon RDS cross-region read replicas use asynchronous replication, satisfying the 1-hour RPO target with minimal overhead and without running standby write instances.
Synchronous Multi-AZ deployments are restricted to a single region and cannot be used for cross-region disaster recovery.
3
Validate the deployment method for the application tier during a failover.
Using AWS CloudFormation to spin up stateless EC2 instances on-demand fits the Pilot Light strategy. Because provisioning EC2 instances takes only a few minutes, it comfortably fits within the 30-minute RTO.
This minimizes ongoing idle compute costs while ensuring the application tier can be quickly established and mapped to the promoted database.

Key Concept

Disaster Recovery Strategies (Pilot Light vs. Warm Standby)
Rate this question

Topics

Disaster Recovery Strategies

More questions from this topic