Microsoft Certified: Azure Fundamentals (AZ-900) 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer is the concept of an Availability Zone, which represents a combination of a fault domain and an update domain within Microsoft Azure's architecture.

Availability Zones are essential for building resilient and highly available applications. A fault domain is a set of hardware components that share a single point of failure, meaning if a failure occurs, it affects all components within that fault domain. Update domains, on the other hand, are used during planned maintenance or system updates, ensuring that not all instances of an application are taken down simultaneously.

By combining these two concepts, Availability Zones allow Azure to distribute resources across different physical locations within a region. This design improves resilience to hardware failures and facilitates seamless application updates since different instances can be updated independently based on their update domain, all while maintaining availability.

With this framework, applications can be architected to withstand both hardware failures (by spreading resources across different fault domains) and maintenance activities (by utilizing multiple update domains), thereby ensuring higher reliability and uptime.