AWS Architecture Blog·August 13, 2026Designing for Data Residency and Disaster Recovery on AWS
This article explores architectural strategies for meeting stringent data residency requirements while ensuring robust disaster recovery on AWS. It details three distinct approaches: leveraging cryptographic boundaries for cross-region replication, utilizing AWS Outposts for in-country hybrid cloud recovery, and implementing strict local autonomy with on-premises or multi-cloud solutions. The core focus is on balancing regulatory compliance with recovery time objectives and data availability.
Read original on AWS Architecture BlogData residency is a critical concern for many industries and government agencies, dictating where data must physically reside. This article outlines architectural patterns to ensure compliance with these regulations while also achieving disaster recovery objectives, which often involve data replication across different geographical locations. It emphasizes that these requirements necessitate careful planning and collaboration with regulators.
Strategy 1: Cryptographic Boundary for Cross-Region Recovery
The first strategy involves replicating encrypted data to an AWS Region in a geopolitically aligned country with similar data protection frameworks. The key mechanism here is the use of AWS Key Management Service (KMS) for server-side or client-side encryption. Crucially, KMS key policies can be configured to explicitly deny decryption operations in the recovery Region, ensuring data remains unreadable until these policies are modified as part of an approved recovery process. This provides a strong technical control to maintain data residency while still benefiting from multi-Region redundancy.
Key Control Enhancement
To further strengthen control over decryption, consider requiring Multi-Factor Authentication (MFA) for updating KMS key policies. This can involve distinct teams or even a trusted third party holding the MFA device, adding an extra layer of security and auditability to data access in a recovery scenario.
Strategy 2: Data Boundary with AWS Outposts
For stricter residency requirements where data must remain within a specific country, even during recovery, AWS Outposts provide a hybrid cloud solution. Backups or pilot light environments can be maintained on Outposts infrastructure located on-premises within the source country. Data is replicated from the primary AWS Region to the Outposts using services like AWS DataSync. While the data plane (compute, storage) resides on-premises, the control plane for managing Outposts infrastructure is hosted in a parent AWS Region. It's recommended to select a parent Region different from the primary workload's Region to avoid correlated failures. This strategy ensures physical data residency while offering a consistent AWS experience.
Strategy 3: Strict Local Autonomy (On-premises or Multi-cloud)
The most stringent residency frameworks require both customer data and its control plane systems to remain entirely within national borders. This strategy offers two options: *On-premises infrastructure* involves self-managing backups from AWS S3 to local storage using tools like AWS DataSync, with data encryption managed on-premises independently of AWS. *Multi-cloud* leverages another cloud provider for backup replication and recovery, often employing a 'lifeboat strategy' where critical systems can be launched in the alternate cloud. Both options provide maximum local autonomy but typically incur higher operational overhead and complexity compared to the other strategies.
- Considerations for Strict Local Autonomy:
- On-premises encryption management must be robust and independent.
- Multi-cloud requires careful planning for data format compatibility and workload portability.
- Both options demand extensive testing to ensure recovery objectives are met.