AWS Certified SysOps Administrator – AssociateReliability and Business ContinuityMedium
A company is implementing a disaster recovery (DR) strategy for its critical application hosted on AWS. The Recovery Time Objective (RTO) is 4 hours, and the Recovery Point Objective (RPO) is 1 hour. The application uses EC2 instances, an Amazon RDS database, and Amazon S3 for static content. The SysOps Administrator needs to select a DR strategy that meets these objectives cost-effectively. Which strategy is most appropriate?
- AMulti-site Active/Active (RTO: near-zero, RPO: near-zero).
- BBackup and Restore (RTO: days, RPO: hours).
- CWarm Standby (RTO: minutes, RPO: seconds).
- DPilot Light (RTO: tens of minutes, RPO: minutes).
Show answer & explanationAnswer & explanation
Correct answer: D. Pilot Light (RTO: tens of minutes, RPO: minutes).
Pilot Light typically offers RTOs in tens of minutes and RPOs in minutes, which aligns well with the company's requirements of RTO 4 hours and RPO 1 hour. It's also more cost-effective than Warm Standby or Multi-site, as only essential core services are running in the DR region.
Why the other options are wrong
- A. Multi-site Active/Active provides near-zero RTO/RPO but is the most expensive and complex, exceeding the requirements and cost-effectiveness goal.
- B. Backup and Restore has RTOs in hours or days, and RPOs in hours, which might meet RPO but likely exceeds RTO if it's 'days'.
- C. Warm Standby offers much lower RTO/RPO than required, leading to higher costs than necessary.
Pilot Light DR Strategy
A disaster recovery strategy where a minimal operational version of an application is always running in a DR region, ready to be scaled up quickly in case of a disaster.
- Core services (e.g., database) are replicated and running.
- Compute resources (e.g., EC2) are scaled down or off.
- Offers better RTO/RPO than Backup and Restore, but less than Warm Standby or Multi-site.
- Cost-effective compared to active-active solutions.
Memory trick: RTO/RPO: How fast, how fresh? Pilot Light's a cost-effective guess!