This image shows a region with 3 availability domains. The region provides identity and access management (IAM) and Cloud Guard security, as well as backup and restore, object storage, and file storage services for the region.

The region provides a single virtual cloud network (VCN) with a direct routing gateway (DRG) and a network address translation (NAT) gateway for secure communications, and 3 subnets arranged as functional tiers.

• Frontend subnet: Provides bare metal and virtual machine compute instances in each of the availability domains. This tier communicates with the database tier and with backup and restore services.
• Database subnet: Provides Database Service and Autonomous Database in availability domain 1, two Database Service instances in availability domain 2 and a single instance of the Database Service in availability domain 3. This tier communicates with regional object storage and file storage.
• Backend (HPC) subnet: Provides instance pools in each of the availability domains. This tier communicates with regional file storage.