Storage Architecture

Canonical hub for storage architecture: backend platform choices, OpenShift integration, and protection constraints.

Scope

In scope

• Storage backend choices and profiles: Storage backend topic and Ceph investigation context.
• Ceph architecture baseline and open design gates: Ceph Architecture.
• Storage work package scope: WP-04 DC3.0 Storage

Out of scope

• Physical storage procurement details beyond architecture decisions.

Current target direction: external RHCS/Ceph as storage backend with ODF external mode for OpenShift integration.

Key Concepts

• Distributed storage platform baseline: Block, File, and S3 Storage.
• Kubernetes storage integration: Block, File, and S3 Storage.
• Storage stack layering (ODF external mode): external RHCS/Ceph provides storage services; ODF provides operators/CSI in OpenShift.
• Lifecycle and interoperability: RHCS lifecycle is managed separately; upgrades and connection credentials must be coordinated to maintain ODF-to-RHCS interoperability.
• ODF external mode prerequisites: version compatibility checks, required connectivity, and secret lifecycle management.

Related Decisions (ADRs)

• ADR-001 Storage backend selection (accepted)
• ADR-009 ODF structure (accepted)
• ADR-014 Encryption at rest (accepted)

Supporting Facts

• block-file-s3-storage
• block-file-s3-storage
• Ceph
• ODF

Key Sources

• Red Hat OpenShift High Level Design

Diagrams

• Implementation dependency and sequencing view: WP-04 DC3.0 Storage.

Mapping Views

• DC 3.0 capability-to-solution mapping for this domain: DC 3.0 Building Block Lens.

Next Steps

1. Capture storage investigations in 10-topics/storage/.
2. Update storage architecture notes under 20-architecture/storage/.
3. Add storage ADRs under 30-decisions/storage/.
4. Keep storage facts current in 40-facts/.