Architecture where multiple systems run simultaneously and share the workload. Like having two engines powering one plane at the same time.
Global websites use active-active configurations across multiple regions so if one data center fails, the others handle all traffic seamlessly.
Active-active is an architecture pattern (not a single managed service). In practice, you implement it using global load balancing, health checks, multi-region deployments, and data replication. Each cloud offers building blocks (global traffic managers, load balancers, DNS, and replication services) to distribute traffic across multiple active sites at the same time.