A global ride-sharing company needs to ensure that its application, which relies heavily on backend microservices running on Amazon EC2, can continue operating even if an entire AWS Region becomes unavailable. The company has a Recovery Time Objective (RTO) of 4 hours and a Recovery Point Objective (RPO) of 1 hour. They want a cost-effective solution that minimizes idle infrastructure while still meeting DR objectives. Which disaster recovery strategy is most appropriate?
- ABackup and Restore across regions.
- BWarm Standby deployment in a secondary region.
- CMulti-Region Active-Active deployment.
- DPilot Light deployment in a secondary region.
Show answer & explanationAnswer & explanation
Correct answer: D. Pilot Light deployment in a secondary region.
A Pilot Light strategy is cost-effective as it keeps a minimal set of core resources running in a secondary region, minimizing idle infrastructure costs. For an RTO of 4 hours and RPO of 1 hour, this strategy allows for sufficient time to scale up the necessary resources (EC2 instances, databases, etc.) from the pilot light environment and restore data from backups/replication, meeting the specified objectives without the higher cost of Warm Standby or Active-Active.
Why the other options are wrong
- A. Backup and Restore typically has an RTO much higher than 4 hours as it involves provisioning all infrastructure from scratch and restoring data.
- B. Warm Standby would be more expensive due to more infrastructure running in the secondary region, offering a lower RTO than required, thus over-provisioning for the given RTO.
- C. Multi-Region Active-Active is the most expensive strategy, with the lowest RTO/RPO (minutes/seconds), which is far more stringent than the company's requirements, leading to significant over-provisioning.
Pilot Light DR Strategy
A disaster recovery strategy where a minimal version of the application is always running in a secondary region, ready to be scaled up to full capacity in case of a disaster.
- Cost-effective by minimizing idle resources.
- Faster RTO than Backup and Restore.
- Requires scaling up resources and promoting databases during recovery.
Memory trick: Pilot Light is like leaving a tiny nightlight on, ready to flip the main switch.