AWS Well-Architected Framework

Six Pillars

Pillar	Tagline	Key ideas
Operational Excellence	Run it well, improve how you run it.	Ops as code, small reversible changes, learn from failure
Security	Protect data, systems, assets.	Strong identity foundation, traceability, defense at every layer, humans away from data
Reliability	Works when expected, recovers when not.	Test recovery, scale horizontally, stop guessing capacity
Performance Efficiency	Right resources, right size, keep it that way.	Serverless, go global fast, experiment often, mechanical sympathy
Cost Optimization	Business value at lowest price point.	Consumption model, attribute spend, kill undifferentiated heavy lifting
Sustainability	Shrink the environmental footprint of the workload.	Maximize utilization, adopt efficient offerings, reduce downstream impact

Reliability vs Performance Efficiency — Both scale, different reason.
- Reliability scales for fault tolerance (“survive losing an AZ”).
- Performance scales for latency and throughput (“serve the traffic fast”).
- Reliability asks does it work; Performance asks does it work fast enough.
Operational Excellence vs Reliability
- Operational Excellence is people and process: runbooks, observability practice, change discipline.
- Reliability is a system property: recovery, fault isolation, capacity.
- One is how the team behaves, the other is how the architecture behaves.
Cost Optimization vs Sustainability — Usually aligned, not identical.
- Cost is dollars.
- Sustainability is carbon and resource footprint.
- Right-sizing serves both.
- Region choice can be greener without being cheaper — that is where they split.
Security vs Reliability on availability
- General availability lives in Reliability.
- Security owns confidentiality, integrity, and availability under attack (DDoS, blast radius).
- [availability under attack] is the only real overlap.

AWS Well-Architected Tool is a service that helps you review and improve your cloud workloads against established architectural best practices.