| name | data-architecture |
| description | Objective-first data architecture design and decision framework. Establish the target object FIRST (BI, ML, or both), elicit requirements and constraints (cloud vs. on-prem, resource/compute budget, team skills, latency and freshness SLAs, compliance), then design the layered architecture and recommend a model — evaluating cost-effectiveness per layer across Azure, AWS, and GCP. Use this skill whenever the user is planning a new data platform or a major redesign, deciding cloud vs. on-prem, choosing between clouds/warehouses at the architecture level, or asking "how should I structure this whole thing". This is a ROUTER/FRAMEWORK: it owns objective and constraint elicitation and the layer design, and delegates cloud-service specifics to cloud-infra-data and pricing detail to cost-optimization-data. |
Data Architecture Design (Framework + Router)
Architecture is decided by the objective and the constraints, not by tooling fashion. This skill runs the decision conversation top-down, then routes to the focused cloud and cost skills for the specifics. Don't restate cloud/pricing detail here — invoke the sub-skills.
Step 1 — Know the object first
Before anything, pin down what the platform is for. The object changes every downstream choice.
| Objective | What it demands of the architecture |
|---|
| BI / analytics | Batch-friendly, star/OBT models, warehouse-centric, cost per query matters, SQL consumers |
| ML | Point-in-time-correct features, offline+online stores, reproducibility, feature freshness → hands to [[ml-feature-engineering]] |
| Both | Shared curated layer feeding a BI mart and an ML feature layer — design the split explicitly |
| Operational / real-time | Streaming backbone, low latency → hands to [[data-pipelines]] (streaming) |
Step 2 — Elicit requirements & constraints (ask, don't assume)
Work through these with the user explicitly. Missing answers are the #1 cause of wrong architecture.
- Deployment: cloud, on-prem, or hybrid? Any mandate (data residency, existing contracts)?
- Resource budget: how much compute can you actually run? How many concurrent jobs? Team size and skills (SQL-only? Spark? Kubernetes)?
- Cost ceiling: monthly budget, and is spend fixed (reserved) or variable (on-demand)?
- Latency / freshness SLA: real-time, hourly, daily? Drives batch vs. streaming.
- Volume & growth: current size and 12-month projection (from [[data-sourcing]] inventory + [[data-profiling]] sizing).
- Compliance: PII, PDPA/GDPR/HIPAA, audit → hands to [[data-reliability]] (governance).
On-prem vs. cloud — the short decision
- Cloud when: elastic/spiky load, small ops team, fast start, variable volume, want managed services.
- On-prem when: hard data-residency mandate, very stable predictable load at large scale where owned hardware beats rental, or existing heavy investment.
- Hybrid when: sensitive data must stay on-prem but burst compute is cheaper in cloud.
Step 3 — Design the layers, price each one
Design layer by layer. For each layer, choose the service and estimate cost — and this is where you route.
| Layer | Purpose | Decide | Route to |
|---|
| Ingestion | Get data in (batch/stream/CDC) | Connector, batch vs. stream | [[data-pipelines]] |
| Storage (raw) | Durable landing zone | Object store layout, format, partitioning | cloud-infra-data |
| Processing | Transform/curate | Warehouse-native SQL vs. Spark vs. serverless | cloud-infra-data |
| Serving | BI marts / ML features / APIs | Warehouse, feature store, cache | cloud-infra-data, [[ml-feature-engineering]] |
| Cost of each | Is this layer cost-effective? | On-demand vs. reserved, tiering | cost-optimization-data |
Routing is mandatory here: for any cloud service selection call Skill(skill="cloud-infra-data"); for any per-layer or whole-platform cost estimate call Skill(skill="cost-optimization-data"). Combine their output into the architecture — don't guess pricing or service limits from memory.
Step 4 — Cross-cloud cost-effectiveness
When the cloud isn't mandated, compare Azure / AWS / GCP per layer rather than picking a vendor wholesale — the cheapest storage and the cheapest compute are often on different clouds, but egress and integration cost usually favor consolidating. Get the concrete numbers from cost-optimization-data and the service mapping from cloud-infra-data, then recommend:
- A primary cloud (consolidation usually wins on egress + ops simplicity), and
- The warehouse/engine (BigQuery vs. Snowflake vs. Redshift vs. Synapse vs. Databricks) justified against the objective and budget.
Step 5 — Recommend & document
Deliver: a one-page architecture (layers + chosen services), the model recommendation (BI/ML/both), the constraint assumptions it rests on, and the estimated cost per layer. State what would change the recommendation (e.g. "if volume 10×, switch to reserved slots").
Hand-off
Feeds the build → [[data-pipelines]] and [[medallion-design]]; the model → [[data-modeling]]; governance → [[data-reliability]]. Upstream inputs come from [[data-sourcing]] and [[data-profiling]]. Lifecycle overview: [[data-lifecycle]].
