# SUS01-BP01 - Choose Region based on both business requirements and sustainability goals

Best practice: SUS01-BP01
Pillar: Sustainability
Source: https://wellarchitected.cloudvisor.eu/docs/sustainability/sus01-bp01.html

## Implementation Guidance

Use "Choose Region based on both business requirements and sustainability goals" to make architecture and operational choices based on evidence rather than assumptions. Define clear criteria, collect current-state data, and compare options against business outcomes and risk tolerance.

For the question "How do you select Regions to support your sustainability goals?", define measurable outcomes, assign owners, and review execution regularly. Integrate this practice into delivery and operations processes so improvements persist as workloads and requirements evolve.

### Key Steps

1. **Define decision criteria and scope**:
   - Document what "Choose Region based on both business requirements and sustainability goals" must address in your environment
   - Set quantitative and qualitative criteria for comparing options
   - Identify stakeholders who approve final decisions

2. **Perform analysis with objective evidence**:
   - Collect metrics, constraints, and dependency data from current operations
   - Compare alternatives against reliability, performance, and risk outcomes
   - Record tradeoffs and assumptions in an architecture decision log

3. **Operationalize and revisit decisions**:
   - Implement selected decisions with explicit owner accountability
   - Define review triggers for demand, risk, or architecture changes
   - Update standards and patterns based on observed outcomes

## Risk / Impact

**Level of risk if not implemented**: Medium

**Impact**: Without this best practice, workloads typically accumulate inefficiencies and execution drift that increase failure probability over time. Problems often surface during traffic spikes, major releases, or dependency failures.

**Benefits of implementation**:
- More predictable operational and engineering outcomes
- Better alignment between architecture decisions and business goals
- Continuous improvement through measurable feedback loops

## AWS Services to Consider

<div class="aws-service">
  <div class="aws-service-content">
    <h4>Amazon CloudFront</h4>
    <p>Caches content at edge locations to reduce latency and origin load.</p>
  </div>
</div>

<div class="aws-service">
  <div class="aws-service-content">
    <h4>Amazon Route 53</h4>
    <p>Provides DNS routing policies and health checks for traffic optimization.</p>
  </div>
</div>

<div class="aws-service">
  <div class="aws-service-content">
    <h4>AWS Organizations</h4>
    <p>Applies governance controls across accounts so operational and architectural standards stay consistent.</p>
  </div>
</div>

<div class="aws-service">
  <div class="aws-service-content">
    <h4>AWS Cost Explorer</h4>
    <p>Analyzes usage and spend trends to support sustainability and efficiency decisions.</p>
  </div>
</div>

## Related Resources

<div class="related-resources">
  <h2>Related Resources</h2>
  <ul>
    <li><a href="https://docs.aws.amazon.com/wellarchitected/latest/framework/sus-01.html">SUS01: How do you select Regions to support your sustainability goals?</a></li>
    <li><a href="https://docs.aws.amazon.com/wellarchitected/latest/sustainability-pillar/welcome.html">AWS Well-Architected Framework - Sustainability Pillar</a></li>
    <li><a href="https://docs.aws.amazon.com/wellarchitected/latest/sustainability-pillar/design-principles.html">Sustainability Design Principles</a></li>
  </ul>
</div>