How do DR plans handle power outages?

Disaster Recovery (DR) plans handle power outages by combining redundant power infrastructure, automated failover systems, and rigorous testing to minimize downtime. When a power outage occurs, the immediate goal is to keep critical systems running and ensure data integrity. This involves layers of backup power sources, such as uninterruptible power supplies (UPS) and generators, paired with procedures to shift workloads to unaffected locations. Developers and operations teams design these systems to activate automatically, reducing the need for manual intervention during emergencies.

The first layer of defense is typically a UPS, which provides short-term battery power to servers and networking equipment. For example, a UPS might keep systems online for 10–30 minutes, allowing time for backup generators to start. Generators, often fueled by diesel or natural gas, take over for extended outages. Cloud-based systems might rely on geographically distributed data centers—if one region loses power, traffic is rerouted to another. For instance, a company using AWS might configure its workloads across multiple Availability Zones, with Route 53 health checks triggering DNS failover if an outage is detected. On-premises setups might use load balancers to redirect traffic to a secondary data center. These systems often rely on automation tools like Kubernetes or Terraform to manage resource allocation during transitions.

Regular testing and monitoring are critical to ensure DR plans work as intended. Teams simulate power outages using controlled scenarios, such as unplugging a server rack or triggering a failover via scripts, to validate response times and data consistency. Monitoring tools like Prometheus or CloudWatch track power status, generator fuel levels, and system health to alert teams proactively. For example, a financial institution might run quarterly drills to switch trading platforms to a backup site, verifying that transaction logs sync correctly. Documentation, such as runbooks, guides responders through steps like restoring databases from backups or validating cryptographic checksums. By combining infrastructure redundancy, automation, and iterative testing, DR plans aim to reduce recovery time objectives (RTO) and prevent data loss during power disruptions.