Overview
Multi-AZ (Availability Zone) deployment is a core best practice for building resilient cloud applications. By distributing resources across physically separate data centers within a region, you protect your application from power outages, fires, or other issues affecting a single facility.
How it Works (Databases)
In a Multi-AZ database setup, the provider maintains a synchronous 'standby' replica in a different AZ. If the primary instance fails, the service automatically fails over to the standby, usually with no data loss and minimal downtime.
How it Works (Compute)
For compute resources, you run instances in multiple AZs behind a load balancer. If one AZ goes down, the load balancer stops sending traffic to that zone, and the remaining instances continue to serve requests.
Importance
Essential for meeting high uptime SLAs and ensuring business continuity.