A regulated lending platform runs on Amazon EC2 and Amazon RDS for PostgreSQL in one Region. The disaster recovery plan allows a recovery time objective of four hours and a recovery point objective of fifteen minutes, and the business wants the lowest steady-state cost that still meets both targets. Which cross-Region disaster recovery approach should the architect adopt?
- AKeep nightly EBS snapshots and RDS automated backups copied to the second Region, then restore and launch the full environment only when a disaster is declared.
- BRun a continuously scaled-down copy of the application fleet and database in the second Region behind a load balancer, ready to scale up on failover.
- COperate a fully scaled active-active deployment across both Regions with traffic split by Amazon Route 53 latency records at all times.
- DReplicate data continuously to a switched-off core in the second Region using an RDS cross-Region read replica, keeping application servers as ready-to-scale images that launch on failover. Correct
Why A is wrong: Daily backups are the cheapest option but a nightly recovery point breaches the fifteen-minute RPO, so this fails the data-loss target even though the RTO might be met.
Why B is wrong: A warm standby meets both targets but keeps compute always running, so it costs more than needed for a four-hour RTO and is not the lowest-cost fit.
Why C is wrong: Multi-site active-active gives the best recovery but duplicates the entire production footprint, making it by far the most expensive choice for these relaxed targets.
Why D is correct: A pilot light keeps the database replicating to hold RPO near minutes while compute stays off, giving the lowest running cost that still meets a four-hour RTO.