A global SaaS provider uses Azure Front Door to route traffic to its multi-region application. The SRE team wants to implement a disaster recovery strategy that ensures continuous availability for users even if an entire Azure region becomes unavailable. The primary goal is to minimize user-perceived downtime and latency. Which disaster recovery pattern, coupled with Azure Front Door, would be MOST effective?
- AWarm Standby deployment in a secondary region.
- BPilot Light deployment in a secondary region.
- CActive-Active deployment across multiple regions.
- DBackup and Restore with Azure Site Recovery.
Show answer & explanationAnswer & explanation
Correct answer: C. Active-Active deployment across multiple regions.
The primary goals are 'continuous availability' and 'minimize user-perceived downtime and latency' even if an 'entire Azure region becomes unavailable'. This points directly to an Active-Active deployment. Azure Front Door is an ideal fit, as it can route traffic intelligently to the closest healthy backend in multiple regions, providing global load balancing and instant failover in case one region fails. The other options involve some level of downtime during failover or recovery, which contradicts 'continuous availability'.
Why the other options are wrong
- A. Warm Standby has a pre-provisioned, scaled-down environment, but still requires a switch-over and scaling up, leading to some downtime, albeit less than Pilot Light. It doesn't guarantee 'continuous availability' seamlessly.
- B. Pilot Light requires scaling up resources in the secondary region, which introduces a recovery time (minutes to hours) and thus user-perceived downtime, failing the 'continuous availability' requirement.
- D. Backup and Restore involves significant downtime (hours to days) and does not provide 'continuous availability' or 'minimal user-perceived downtime'.
DR Strategy: Active-Active
A disaster recovery strategy where the application is fully deployed and actively serving traffic from multiple, geographically separated regions simultaneously. Traffic is distributed across all active regions, and failover is typically instantaneous.
- Provides the highest level of availability and lowest RTO/RPO.
- Often uses global load balancers (like Azure Front Door) for traffic management.
- Requires real-time or near real-time data synchronization.
- Most complex and expensive to implement.
Memory trick: Continuous Availability: 'Front Door to Active-Active, always on!'