This image shows the post-migration architecture after the on-premises Oracle Database is migrated to a Oracle Base Database Service VM database system in Oracle Cloud Infrastructure

The on-premises Oracle Database deployment has an application server. A Site-to-Site VPN connects the on-premises data center to a dynamic routing gateway on the VCN of the OCI Region. Information flows from the customer data center to the Application Tier and the Database Tier.

The OCI region has one availability domain and three fault domains.
The region has a VCN across all three fault domains with the following private regional subnets:
- Application tier: Compartment A in the application tier has an OCI Load Balancer in Fault Domain 1 and an Application Server Compute in Fault Domain 2.
- Database tier: Compartment B in the database tier has a Client subnet with Oracle Base Database Service in Fault Domain 1.
Security lists are used to regulate traffic to and from the subnets.
Route tables are used to direct traffic bound for destinations outside the VCN.
A Dynamic Routing Gateway enables private connectivity from the on-premises data center to the private subnets, using site-to-site VPN.
A Service Gateway enables Oracle Base Database Service in the private subnet of the Database Tier to communicate with Oracle Cloud Infrastructure Object Storage.

The following services are available Oracle Services Network:

OCI Object Storage
Logging
OCI IAM
Monitoring
Other Oracle Cloud Services

Oracle Database Zero Data Loss Autonomous Recovery Service is located in the OCI Region and connects to the Oracle Base Database Service through a private endpoint.