Current view: August 2026. OCI service capabilities change often, so this article links every claim back to Oracle's documentation.
Executive summary
A common OCI architecture question is which Oracle Database versions and deployment topologies are available on Base Database Service (DBCS), Exadata Database Service on Dedicated Infrastructure (ExaDB-D, formerly commonly referred to as ExaCS) and Exadata Database Service on Exascale Infrastructure (ExaDB-XS).
Base Database Service
Shape and storage type affect topology.
Exadata on Dedicated Infrastructure
Older releases can remain supported on existing 19c VM clusters with upgrade support.
Exadata on Exascale Infrastructure
Single-VM VM clusters are available for single-instance workloads.
The key clarification is that Oracle RAC has not been removed from DBCS. Oracle's current documentation explicitly states that Base Database Service provides both single-node DB systems and multi-node RAC DB systems, with Enterprise Edition, Extreme Performance (EE-EP) required for multi-node RAC.
EE-EP retirement on Base Database Service
Oracle has announced the retirement of the EE-EP software edition on Base Database Service, effective July 31, 2026. Existing deployments continue to run, but new provisioning and contract renewals are affected. Because multi-node RAC on DBCS requires EE-EP, validate any new DBCS RAC deployment with Oracle. Oracle points EE-EP workloads to ExaDB-XS.
- Existing deploymentsContinue to run
- July 31, 2026EE-EP retirement effective
- New provisioning and renewalsAffected; Oracle points EE-EP workloads to ExaDB-XS
1. Current high-level matrix
| Service | 26ai | 21c | 19c | Single instance | RAC | Important qualification |
|---|---|---|---|---|---|---|
| Base Database Service (DBCS) | Yes | Yes | Yes | Yes | Yes | RAC requires EE-EP, which is retiring for new provisioning from July 31, 2026. Shape and storage type affect topology. |
| ExaDB-D / ExaCS | Yes | No* | Yes | Yes | Yes | Current service documentation lists 26ai and 19c; older releases can remain supported on existing 19c VM clusters with upgrade support. |
| ExaDB-XS / Exascale | Yes | No | Yes | Yes | Yes | Supports 26ai and 19c. Single-VM VM clusters are available for single-instance workloads. |
* 21c is not listed as a currently supported ExaDB-D database version in the current service description. Check existing environments and older releases against Oracle's current support and upgrade documentation before making a migration decision.
2. Base Database Service (DBCS)
Oracle Base Database Service supports Oracle AI Database 26ai, Oracle Database 21c and Oracle Database 19c. It supports both single-node DB systems and two-node RAC DB systems.
DBCS version availability depends on the shape
| DBCS shape | 26ai | 21c | 19c | Notes |
|---|---|---|---|---|
| Ampere A1 | Yes | No | Yes | Single-node only |
| AMD E5 | Yes | No | Yes | RAC possible, subject to RAC requirements |
| AMD E4 | Yes | Yes | Yes | RAC possible, subject to RAC requirements |
| Intel X9 | Yes | Yes | Yes | RAC possible, subject to RAC requirements |
| Intel X7 | Yes | Yes | Yes | RAC supported subject to shape constraints; VM.Standard2.1 is single-node only |
| VM.BaseDB.x86 | Yes | No | Yes | Generation-agnostic. Single-node only; SE, EE and EE-HP on LVM |
| VM.Standard.x86 | Yes | No | No | Generation-agnostic. Single-node only; shape retiring July 31, 2026 |
Version support on Ampere A1, AMD E5, AMD E4 and Intel X9 starts at specific minimum Release Updates (for example, 19.19 or later on Ampere A1 and 19.21 or later on AMD E5). Check the shape documentation for the exact RU.
Oracle states that multi-node RAC DB systems require a minimum of two OCPUs per node and ASM; RAC DB systems cannot be created using Logical Volume Manager. Ampere A1 and the generation-agnostic x86 shapes are single-node only.
3. Exadata Database Service on Dedicated Infrastructure (ExaDB-D / ExaCS)
The current Oracle service description lists Oracle AI Database 26ai and Oracle Database 19c as supported database versions. Older database versions (12.2, 12.1 and 11.2) are also documented as supported with Upgrade Support, primarily in the context of existing 19c cloud VM clusters.
Exadata Database Service uses Enterprise Edition, Extreme Performance or an eligible BYOL model. The Extreme Performance option includes Oracle RAC. ExaDB-D therefore remains the Exadata option when the architecture requires Exadata infrastructure and RAC, while still allowing single-instance database deployments.
4. Exadata Database Service on Exascale Infrastructure (ExaDB-XS)
The current ExaDB-XS documentation lists Oracle AI Database 26ai and Oracle Database 19c as supported database releases. Enterprise Edition, Extreme Performance includes Oracle RAC.
A point that often causes confusion is that ExaDB-XS is no longer effectively "RAC only". Oracle made single-VM VM clusters generally available in January 2025. A VM cluster can run with one VM for a single-instance workload, or be scaled to multiple VMs for a RAC deployment.
Even with a single VM, Oracle notes that the RAC components and RAC networking setup are still present. The single-VM capability is intended for workloads that do not require the availability characteristics or licensing of a multi-node RAC cluster.
5. RAC: what has actually changed?
The statement "RAC is no longer available on DBCS" is not supported by the current Oracle documentation, which still describes multi-node RAC DB systems. What has changed is the edition RAC depends on: EE-EP on DBCS is being retired for new provisioning from July 31, 2026, so plan any new DBCS RAC deployment with that in mind.
Single-node and multi-node RAC are documented. New EE-EP provisioning, and therefore new RAC, is affected by the July 31, 2026 retirement.
RAC is available through the Enterprise Edition, Extreme Performance capability.
RAC is available, and single-VM VM clusters also allow single-instance workloads.
6. Architecture decision guide
Find the likely fit
Choose a requirement to see which services fit and why.
All three can support 19c. DBCS RAC is subject to the EE-EP retirement; choose based on Exadata and workload requirements.
View the full decision table
| Requirement | Likely fit | Why |
|---|---|---|
| 19c + RAC + VM-based OCI database service | ExaDB-D / XS, or DBCS | All three can support 19c. DBCS RAC is subject to the EE-EP retirement; choose based on Exadata and workload requirements. |
| 21c + RAC | DBCS | Current DBCS documentation lists 21c, with availability depending on shape. Subject to the EE-EP retirement; ExaDB-XS is Oracle's stated target for EE-EP workloads. |
| 26ai + RAC | ExaDB-XS, ExaDB-D or DBCS | All three support 26ai. DBCS RAC is subject to the EE-EP retirement; topology and infrastructure requirements determine the best fit. |
| 26ai + single instance | DBCS, ExaDB-D or ExaDB-XS | All can support single-instance deployment, subject to shape and VM-cluster constraints. |
| Exadata infrastructure required | ExaDB-D or ExaDB-XS | Use the Exadata service family. |
| Single instance on ExaDB-XS | ExaDB-XS | Use a single-VM VM cluster. |
7. Key takeaways
- RAC is still documented on DBCS, but its required edition (EE-EP) is being retired for new provisioning from July 31, 2026.
- DBCS currently supports 26ai, 21c and 19c, but version availability varies by compute shape and minimum Release Update.
- DBCS RAC requires EE-EP and a supported RAC configuration, and RAC requires ASM rather than LVM.
- ExaDB-D currently lists 26ai and 19c as its primary supported database versions, with older versions available under documented upgrade-support conditions.
- ExaDB-XS currently supports 26ai and 19c and supports both multi-node RAC and single-VM deployments (single-VM clusters still run the RAC components).
- The right architecture decision weighs database release, shape or VM-cluster type, RAC requirement, licensing, Exadata requirement and operational requirements together.
Note: OCI service capabilities and regional availability can change. Validate the target OCI region, shape, database software image and RU, licensing model and current Oracle documentation before production deployment.
8. Oracle references
- Oracle Base Database Service: about and supported versions
- Oracle Base Database Service: DB systems, shapes and RAC constraints
- Oracle Base Database Service: create a DB system
- Exadata Database Service on Dedicated Infrastructure: service description
- Exadata Database Service on Exascale Infrastructure: manage databases
- ExaDB-XS: single VM cluster
