Regions and Availability Domains

Regions are grouped into realms . Your tenancy exists in a single realm and can access all regions that belong to that realm. You cannot access regions that are not in your realm. Currently, Oracle Cloud Infrastructure has multiple realms, including commercial, government, and dedicated realms.

The following table lists the regions in the Oracle Cloud Infrastructure commercial realms :

To subscribe to a region, see Managing Regions.

For a list of regions in the Oracle Government Cloud realms, see the following topics:

• Oracle Cloud Infrastructure US Government Cloud with FedRAMP Authorization
• Oracle Cloud Infrastructure US Federal Cloud with DISA Impact Level 5 Authorization
• Oracle Cloud Infrastructure United Kingdom Government Cloud

To help balance capacity in data centers, Oracle Cloud Infrastructure randomizes availability domains by tenancy . For example, the availability domain labeled PHX-AD-1 for tenancyA might be a different data center than the one labeled PHX-AD-1 for tenancyB.

To track which availability domain corresponds to which data center for each tenancy, Oracle Cloud Infrastructure uses tenancy-specific prefixes for availability domain names. An example prefix is Uocm:. With this prefix, availability domain names are Uocm:PHX-AD-1, Uocm:PHX-AD-2, and so on.

To get the specific names of your tenancy's availability domains, use the ListAvailabilityDomains operation, which is available in the IAM API. You can also see the names when you use the Console to create an instance and choose which availability domain to create the instance in.

A fault domain is a grouping of hardware and infrastructure within an availability domain. Each availability domain contains three fault domains. Fault domains provide anti-affinity: they let you distribute your instances so that the instances are not on the same physical hardware within a single availability domain. A hardware failure or Compute hardware maintenance event that affects one fault domain does not affect instances in other fault domains.

To control the placement of your compute instances, bare metal DB system instances, or virtual machine DB system instances, you can optionally specify the fault domain for a new instance or instance pool at launch time. If you don't specify the fault domain, the system selects one for you. Oracle Cloud Infrastructure makes a best-effort anti-affinity placement across different fault domains, while optimizing for available capacity in the availability domain. To change the fault domain for a compute instance, edit the fault domain. To change the fault domain for a bare metal or virtual machine DB system instance, terminate it and launch a new instance in the preferred fault domain.

Use fault domains to do the following things:

• Protect against unexpected hardware failures.
• Protect against planned outages because of Compute hardware maintenance.

For more information:

• For recommendations about how to use fault domains when provisioning application and database servers, see Fault Domains in Best Practices for Your Compute Instances.

Trial, free tier, and pay-as-you-go tenancies are limited to one subscribed region. You can request an increase to the limit for pay-as-you-go tenancies, see To request a subscribed region limit increase for more information.

Universal monthly credit tenancies can subscribe to all publicly released commercial regions.

All Oracle Cloud Infrastructure regions offer core infrastructure services, including the following:

• Compute: Compute (Intel-based bare metal & VM, DenseIO & Standard), Container Engine for Kubernetes, Container Registry, Artifact Registry
• Storage: Block Volume, File Storage, Object Storage, Archive Storage
• Networking: Virtual Cloud Network, Load Balancer, FastConnect (specific partners as available and requested)
• Database: Database, Exadata Cloud Service, Autonomous Database for Analytics and Data Warehousing, Autonomous Database for Transaction Processing and Mixed Workloads
• Edge: DNS
• Platform: Audit, Identity and Access Management, Monitoring, Notifications, Tagging, Work Requests

• Security: Vault

Generally available cloud services beyond those in the previous list are made available based on regional customer demand. Any service can be made available within a maximum of three months, with many services deploying more quickly. New cloud services are made available in regions as quickly as possible based on a variety of considerations, including regional customer demand, ability to achieve regulatory compliance where applicable, resource availability, and other factors. Because of Oracle Cloud Infrastructure's low latency interconnect backbone, you can use cloud services in other geographic regions with effective results when those services are not available in your home region, as long as data residency requirements do not prevent you from doing so. We regularly work with customers to help ensure effective access to required services.

The following sections list the resource types based on their availability: across regions, within a single region, or within a single availability domain.