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Zorluk: OrtaHigh Availability and Disaster Recovery Design

A municipal smart-grid utility provider is launching a new smart-meter data ingestion system on AWS. The system's primary workload runs in the us-east-1 Region, and the company requires a disaster recovery (DR) solution in the us-west-2 Region. The application requires outbound internet access from its private subnets to register meters. The database tier uses Amazon Aurora PostgreSQL. The business requires a Recovery Time Objective (RTO) of 15 minutes and a Recovery Point Objective (RPO) of 5 minutes. Which design meets these objectives with the lowest cost and operational complexity while maintaining high availability in the primary region?

  1. Configure Amazon Aurora Global Database to replicate data from us-east-1 to us-west-2. Deploy the application servers in both Regions using Auto Scaling groups, keeping the us-west-2 group scaled to a minimum capacity of one instance as a warm standby. Deploy a NAT Gateway in each Availability Zone within us-east-1 for outbound internet access. Configure Amazon Route 53 with a failover routing policy and health checks to route traffic to the secondary Region if the primary Region becomes unhealthy.Cevap
  2. B
    Configure Amazon Aurora database cluster snapshots in us-east-1, and copy them to us-west-2 every 4 hours. Deploy the application servers using AWS CloudFormation templates in us-west-2 only when a disaster is declared. In us-east-1, deploy NAT Gateways in each Availability Zone. Use Amazon Route 53 with a failover routing policy to update DNS records to point to the new resources once the database is restored in the secondary Region.
  3. C
    Configure Amazon Aurora Global Database to replicate data from us-east-1 to us-west-2. Deploy the application servers in both Regions using Auto Scaling groups, keeping the us-west-2 group scaled to a minimum capacity of one instance. In us-east-1, deploy a single NAT Gateway in one Availability Zone to route all outbound internet traffic from all private subnets. Configure Amazon Route 53 with a failover routing policy and health checks to handle regional failover.
  4. D
    Deploy Amazon RDS PostgreSQL in us-east-1 with a Multi-AZ deployment. Direct read-heavy application traffic in the primary region to the standby instance in the secondary Availability Zone to reduce load on the primary writer. Replicate data to us-west-2 using AWS Database Migration Service (DMS) for disaster recovery, and use Amazon Route 53 failover routing for DNS failover.

Cevap

Configure Amazon Aurora Global Database for database replication, run the secondary application tier in a warm standby state with a minimum capacity of one instance, deploy redundant NAT Gateways across Availability Zones in the primary region, and use Route 53 failover routing policy with health checks.
The correct option satisfies the 5-minute RPO using Amazon Aurora Global Database, which offers sub-second cross-region replication. It satisfies the 15-minute RTO by utilizing a warm standby strategy with at least one active instance in the secondary region's Auto Scaling group, allowing the application tier to scale up rapidly during failover. By placing NAT Gateways in each Availability Zone of the primary region, it avoids a single point of failure for outbound traffic. Using Route 53 failover routing policy allows the system to automatically redirect DNS requests to the secondary region if the primary region's ALB health checks fail.

Adım Adım Çözüm

1
Analyze RTO and RPO requirements.
Identify that the 5-minute RPO rules out backup/restore methods with longer intervals, and the 15-minute RTO requires pre-existing database replication (like Aurora Global Database) and a fast application recovery strategy (like Warm Standby).
This establishes the baseline DR strategy that can meet the recovery objectives.
2
Evaluate high availability requirements for the primary region.
Determine that outbound internet connectivity must be highly available, requiring redundant NAT Gateways across multiple Availability Zones in the primary region.
A single NAT Gateway creates a single point of failure, violating high availability principles.
3
Select the correct database and routing configuration.
Choose Aurora Global Database for sub-second cross-region replication, and Route 53 with failover routing policies linked to health checks to manage external traffic redirection.
This ensures the database meets the RPO and DNS failover is automated and reliable.

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High Availability and Disaster Recovery Design
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