Considerations for Architecting Resilient Multi-Region Workloads

What to consider when evaluating a ‘multi-region’ strategy as part of business continuity and disaster recovery planning

Introduction

Increasingly, I hear the term ‘multi-region’ used within the IT community and in conversations with peers and customers, most often within the context of disaster recovery. In my experience, ‘multi-region’ is a cloud provider-agnostic phrase that can mean different things to different organizations. A few examples:

• Multiple, independent, regionally-deployed application instances that better serve a geographically-diverse customer base, for regulated ‘locality-restricted’ workloads, to ensure data sovereignty, distribute system load, or minimize the blast radius of a regional disaster event. Although a disaster recovery plan may be required, the primary driver of this architecture is often not disaster recovery.
• An active-passive failover strategy in which a second DR Region hosts a mixture of cold, warm, and hot copies of workloads and serves as a failover in response to a disaster event in the Primary Region. In my experience, this is probably the most common use case when someone refers to ‘multi-region.’
• An active-active architecture in which data is continually replicated and traffic can be seamlessly routed based on geolocation between all services within two or more geo-redundant regions, making it resilient to the impact of a regional disaster event. Some might describe this architecture as having both inner-regional and inter-regional high availability.

Copyright: peshkov

Terminology

The following terminology is commonly used when discussing Business Continuity and Disaster Recovery Planning. Teams should be familiar with these concepts before undertaking planning activities:

• Fault Tolerance (FT), High Availability (HA), Disaster Recovery (DR), and Business…