Architecture
Open-FDD is a container stack (central / React SPA / fieldbus / mqtt / mcp) with Arrow historian, DataFusion SQL FDD, and Project Haystack semantic model.
| Topic | Document |
|---|---|
| ADR — VAV health matrix | Cohort analytic (not a 60th rule) |
| Services | Stack images and compose roles |
| Data flow | Drivers → model → historian → FDD → UI |
| Storage & DataFusion | Feather historian and SQL rules |
| DataFusion-first | Pandas policy and production SQL rule |
| Job workspaces | Persistent analysis Jobs under workspace/jobs/ |
| Analytics boundary | Typed DF analytics vs React |
Modernization ledgers: React / Rust migration.