Which DR strategy will meet these requirements with the LEAST change to the application stack?
Launch a replica environment of everything except Amazon RDS in a different Availability Zone. Create an RDS read replica in the new Availability Zone, and configure the new stack to point to the local RDS DB instance. Add the new stack to the Route 53 record set by using a health check to configure a failover routing policy.
Launch a replica environment of everything except Amazon RDS in a different AWS Region. Create an RDS read replica in the new Region, and configure the new stack to point to the local RDS DB instance. Add the new stack to the Route 53 record set by using a health check to configure a latency routing policy.
Launch a replica environment of everything except Amazon RDS in a different AWS Region. In the event of an outage, copy and restore the latest RDS snapshot from the primary Region to the DR Region. Adjust the Route 53 record set to point to the ALB in the DR Region.
Launch a replica environment of everything except Amazon RDS in a different AWS Region. Create an RDS read replica in the new Region, and configure the new environment to point to the local RDS DB instance. Add the new stack to the Route 53 record set by using a health check to configure a failover routing policy. In the event of an outage, promote the read replica to primary.
Explanations:
While this option creates a replica environment in a different Availability Zone and includes an RDS read replica, it does not fulfill the requirement for a geographically isolated DR site. Additionally, using a health check for failover is not ideal for RPO and RTO needs since it relies on local resources.
This option proposes creating a DR environment in a different AWS Region, which aligns with the requirement for geographic isolation. However, it mentions configuring the stack to point to the local RDS DB instance, which contradicts the RPO requirement as data loss could occur since the RDS instance in the primary region will not be in sync.
Although it suggests a DR environment in a different AWS Region, it only relies on snapshots for recovery, which does not meet the RPO of 15 minutes. The manual process of adjusting Route 53 after an outage also does not satisfy the RTO requirement effectively.
This option establishes a geographically isolated DR site in another AWS Region and sets up an RDS read replica. It also provides for automatic failover by promoting the read replica to primary, ensuring both the RTO of 4 hours and RPO of 15 minutes are met. Using a failover routing policy in Route 53 supports a quick switch to the DR environment in case of an outage.