True Availability in the Cloud Era: Lessons from AWS Outage History - The Demise of the Multi-AZ Myth and Its Impact on the Physical World
Cloud services, particularly Amazon Web Services (AWS), form an indispensable foundation for modern digital society. However, their massive and complex systems can sometimes fail in ways beyond our imagination, causing severe impacts on business and societal activities. On October 20, 2025, AWS was again hit by a large-scale outage, causing many services to be down for an extended period. This incident once again highlighted the challenge of how to address the risks in a modern society where dependence on the cloud is deepening. ...