SAA-C03 - Design Resilient Architectures (26% of the exam) - Section 2.6

Select disaster recovery strategies such as backup and restore, pilot light, warm standby and multi-site to meet RTO and RPO targets.

Compare the four AWS disaster recovery strategies - backup and restore, pilot light, warm standby, and multi-site active/active - on recovery time objective and recovery point objective, noting that lower RTO and RPO demand higher standing infrastructure cost. Choose a strategy that fits the tolerable downtime and data-loss window, and recognise which AWS services support each approach.

Recovery time objectiveRecovery point objectivePilot lightWarm standby

Practice question for this objective

Free sampleDesign Resilient Architectureshard

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

Match a four-hour RTO and fifteen-minute RPO to the lowest-cost disaster recovery strategy, which is pilot light. Continuous database replication keeps the recovery point within minutes while leaving compute powered off, so only the database incurs steady cost; compute is launched from images during the four-hour recovery window, satisfying both objectives at minimum spend.

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.

See more SAA-C03 practice questions, answers explained.

Exam traps in Design Resilient Architectures

Answers that look right on this material and are not. Each one is a distractor from a different question in the SAA-C03 bank for this domain.

Keep an RDS cross-Region read replica replicating continuously while the application servers stay switched off as ready-to-launch images until failover.
Why it is wrong: Pilot light meets these relaxed targets but pays to run a replica around the clock, so it costs more than backup and restore when an RPO of a full day is acceptable.
Copy automated Aurora snapshots to the second Region every twenty-four hours and restore a new cluster from the latest snapshot only after a disaster is declared.
Why it is wrong: Daily snapshot copies leave a recovery point of up to a day and a restore taking hours, which is backup and restore and cannot meet a seconds-level recovery point.
Document a detailed runbook so the engineer can build the network and compute resources by hand more quickly and consistently during the next failover.
Why it is wrong: A runbook helps consistency but still relies on manual console work, so the slow, error-prone build that drives the long recovery time remains the bottleneck.

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