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Zorluk: OrtaHigh Availability and Disaster Recovery Design

A utility company is deploying a smart water grid telemetry system on AWS. The system must continuously collect telemetry data from thousands of regional flow sensors and store it in a relational database. To protect against a regional outage, the architecture must span two AWS Regions (a primary and a secondary region) with a Recovery Point Objective (RPO) of 55 minutes and a Recovery Time Objective (RTO) of 1515 minutes. The processing applications run on Amazon EC2 instances in private subnets and must periodically send reports to an external compliance service over the public internet. Which two architecture components should a solutions architect recommend to meet these requirements with high availability while minimizing regional failover delay? (Select TWO.)

  1. Configure Amazon Aurora Global Database with the primary cluster in the primary region and a secondary cluster in the secondary region. If a regional failure occurs, promote the secondary cluster to support write traffic, keeping data replication latency under 11 second.Cevap
  2. Deploy a NAT Gateway in each Availability Zone in both regions. Update the route tables of the private subnets to direct outbound traffic (0.0.0.0/00.0.0.0/0) to the local NAT Gateway in the same Availability Zone.Cevap
  3. C
    Use AWS Backup to schedule hourly database snapshots, copy them to the secondary region, and restore the database cluster from the backup copy during a failover event.
  4. D
    Deploy a single NAT Gateway in a single public subnet for each region's VPC, and route all outbound internet traffic from all private subnets in that VPC through this single gateway to save costs.
  5. E
    Configure a Route 53 Private Hosted Zone to resolve internal database endpoints, and associate it only with the VPC in the primary region to prevent cross-region DNS resolution loops.
  6. F
    Use Amazon RDS PostgreSQL with a Multi-AZ deployment in the primary region, and configure the application processing nodes in the secondary region to continuously read from the Multi-AZ standby instance to distribute read traffic.

Cevap

Configure Amazon Aurora Global Database with the primary cluster in the primary region and a secondary cluster in the secondary region, promoting the secondary cluster during a failover. Additionally, deploy a NAT Gateway in each Availability Zone in both regions, updating the route tables of the private subnets to route outbound traffic through their respective local NAT Gateways.
Implementing Amazon Aurora Global Database allows for replication lag of under 11 second and fast cluster promotion in the event of a regional failure, which satisfies the 55-minute RPO and 1515-minute RTO. Deploying a NAT Gateway in each Availability Zone and configuring local VPC routing ensures that outbound internet traffic has no single point of failure within a region, maintaining high availability for reporting services.

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1
Select a replication strategy that supports near-zero data loss and rapid recovery to satisfy the 55-minute RPO and 1515-minute RTO.
Amazon Aurora Global Database provides physical block-level replication with lag under 11 second, and can be promoted to a primary cluster in less than a minute.
Traditional backup and restore methods fail both RPO and RTO requirements, making live cross-region replication mandatory.
2
Ensure outbound connectivity for reporting nodes does not have a single point of failure in any Availability Zone.
By deploying a NAT Gateway in each Availability Zone, subnet route tables can resolve internet-bound traffic locally, preventing a single zone's failure from blocking outbound data.
High availability requires removing single points of failure at the zone level, which is compromised by using a single NAT Gateway.
3
Verify DNS and secondary database accessibility configurations.
Confirm that Private Hosted Zones are associated with all participant VPCs, and that database replication targets are read-capable or promotable rather than passive standbys.
Improper DNS association and attempts to read from passive standbys are common design flaws that prevent successful failovers.

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High Availability and Disaster Recovery Design for Multi-Region Architectures
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