Cloud Disaster Recovery Costs: RTO, RPO and Pricing Models

The Four Disaster Recovery Strategies

AWS, Azure, and GCP all organize disaster recovery into the same four strategy tiers, ordered from cheapest/slowest to most expensive/fastest recovery. Choosing the right tier is fundamentally a cost trade-off against how much downtime and data loss the business can tolerate — there is no single "correct" strategy, only the one that matches your Recovery Time Objective (RTO) and Recovery Point Objective (RPO) at the lowest cost.

What RTO and RPO Actually Cost You

Every step down in acceptable RTO/RPO roughly multiplies infrastructure cost because it requires more standing infrastructure running in the DR region rather than being provisioned on demand. Backup & Restore keeps only backups in the target region — nearly free to maintain but slow to recover, since compute must be provisioned from scratch during an incident. Active-Active keeps a full duplicate production environment running continuously in a second region, which is why it approaches double the cost of the primary deployment alone.

Backup Storage and Retention Costs

Cross-region backup storage (AWS Backup, Azure Backup Vault, GCP Backup and DR) is billed per GB-month stored plus a cross-region transfer fee for the initial copy, typically $0.02–0.05/GB for the copy and $0.02–0.023/GB-month for ongoing storage. Retention policy is the biggest lever here: a compliance requirement to keep 7 years of monthly backups for a 5TB database can result in storing 60x the primary database size over the retention period, even though most of that data will never be restored.

Cross-Region Replication Costs

Warm Standby and Active-Active strategies require continuous data replication to the DR region — database replication (e.g. RDS Cross-Region Read Replicas, Azure SQL Auto-Failover Groups, GCP Cloud SQL cross-region replicas) and storage replication (S3 Cross-Region Replication, Azure geo-redundant storage, GCS multi-region buckets). This replication traffic is billed as inter-region data transfer, typically $0.02–0.08/GB depending on the region pair. A database replicating 500GB/day of changes to a DR region on the US–EU route can generate $300–1,200/month in replication charges alone, on top of the standby compute.

DR Testing and Failover Drill Costs

A DR plan that has never been tested is not a reliable DR plan, but failover drills have their own cost: spinning up the full DR environment to validate a Pilot Light or Warm Standby configuration temporarily doubles compute spend for the duration of the test. Well-run FinOps teams budget for quarterly or semi-annual DR tests as a fixed line item (typically a few hours to a few days of full-scale DR compute) rather than treating it as an unplanned cost, since the alternative — discovering a broken failover during a real incident — is far more expensive in both dollars and downtime.