This image shows a 3-tier deployment in a region with multiple availability domains. The Oracle Cloud region has a VCN with 2 Availability Domains (AD1 and AD2), and 3 subnets (Subnet A, Subnet B, and Subnet C). Data flows from the Dynamic Routing Gateway through FastConnect to the Customer Datacenter.

Subnet A contains the Load Balancers. The active load balancer is in AD1 and the standby load balancer is in AD2.

Subnet B contains the Web Servers. VM1 is in AD1 and VM2 is in AD2.

Subnet C contains the Databases. The active database is in AD1 and the standby database is in AD2. Data Guard Sync flows from the Active to the Standby. RMAN Backup flows from the Standby to Object Storage that resides outside of the VCN.

Information flows from the active load balancer in Subnet A to the VM1 and VM2 web servers in Subnet B, and then from the VM1 and VM2 web servers to the active database in Subnet C.