name: arch_decisions
router_kit: DevOpsKit
description: ADR template, database selection, capacity planning and scalability.
metadata:
skillport:
category: thinking
tags: [arch decisions, architecture, automation, best practices, clean code, coding, collaboration, compliance, debugging, design patterns, development, documentation, efficiency, git, optimization, productivity, programming, project management, quality assurance, refactoring, software engineering, standards, testing, utilities, version control, workflow] - arch-patterns

📋 Architecture Decisions

ADR, database selection and capacity planning.

📝 ADR Template

# ADR-001: Database Selection

## Status: Accepted

## Context
[Problem description]

## Decision
We will use PostgreSQL.

## Consequences
### Positive
- ACID compliance
### Negative
- Horizontal scaling difficult

## Alternatives
- MongoDB: Rejected - Not suitable for JOINs

🗄️ Database Selection

📊 Capacity Planning

DAU: 1M users
Requests: 20/user/day = 20M/day
RPS: 20M / 86400 = ~230 RPS
Peak: 230 × 3 = ~700 RPS

Architecture Decisions v1.0

🔄 Workflow

Source: AWS Architecture Blog

Phase 1: Problem Identification

• [ ] Context: Define the problem and its impact clearly.
• [ ] Constraints: Identify constraints (Budget, Time, Technology).
• [ ] Options: Identify at least 2 alternative solutions.

Phase 2: Proposal (Status: Proposed)

• [ ] Draft: Fill out the ADR template.
• [ ] RFC: Request team comments (Pull Request or Meeting).
• [ ] Evaluation: Score alternatives based on criteria (Pros/Cons).

Phase 3: Decision (Status: Accepted/Rejected)

• [ ] Consensus: Clarify the decision and update status.
• [ ] Implications: Write down long-term effects (Consequences).
• [ ] Commit: Add ADR file to repo.

Checkpoints