SOA-C03 - Reliability and Business Continuity - Section 2.7

Follow disaster recovery procedures and select a strategy across Regions from backup and restore through pilot light and warm standby.

Compare the four DR strategies - backup and restore, pilot light, warm standby, and multi-site active/active - by their cost, recovery time objective, and recovery point objective trade-offs. Apply cross-Region replication to select the minimum-cost strategy that still meets the stated RTO and RPO requirements.

Backup and restorePilot lightWarm standbyCross-Region replication

Practice question for this objective

Free sampleReliability and Business Continuityhard

An internal analytics workload runs in a single Region and is not customer-facing. The business accepts an RTO of up to twenty-four hours and an RPO of up to one day after a regional outage, and the overriding constraint is to spend almost nothing on standby infrastructure between incidents. The team already copies nightly application backups and database snapshots to a second Region. After a regional outage they are willing to provision the entire environment from those copies before the workload returns to service. Which disaster recovery strategy best matches these requirements?

  • AWarm standby, running a permanently on but scaled-down copy of the whole environment in the second Region so it can absorb production load shortly after failover.
  • BBackup and restore, copying backups to the recovery Region and provisioning the whole environment from those copies only after a disaster is declared. Correct
  • CPilot light, keeping the database continuously replicated to a live standby instance in the recovery Region while the application tier remains switched off until failover.
  • DMulti-site active-active, serving the analytics workload from both Regions at the same time with traffic routing that fails over automatically when one Region degrades.
Select backup and restore when relaxed RTO and RPO targets allow rebuilding from cross-Region backups to achieve the lowest standby cost. Backup and restore provisions no recovery infrastructure until a disaster is declared and depends only on backups copied to another Region, so it carries the smallest ongoing cost of the four strategies and suits workloads that can tolerate an RTO of hours and an RPO of up to a day.

Why A is wrong: Warm standby keeps an always-running scaled-down stack, which adds continuous cost that conflicts with spending almost nothing on standby, and its fast RTO exceeds what these relaxed objectives require.

Why B is correct: Backup and restore provisions nothing until failover and relies on cross-Region backup copies, giving the lowest standing cost while meeting a relaxed RTO of hours and an RPO measured in a day.

Why C is wrong: Pilot light needs a continuously replicated, always-on data layer, which costs more than nightly backup copies and delivers a tighter RPO than the one-day objective actually demands.

Why D is wrong: Active-active runs full duplicate capacity serving live traffic, the most expensive option, which directly contradicts the requirement to minimise standby spend for a tolerant internal workload.

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