AWS SAA-C03 Exam Overview

AWS Certified Solutions Architect – Associate (SAA-C03) is one of AWS’s most popular certifications, validating the ability to design secure, highly available systems on AWS.

Exam details:

Duration: 130 minutes
Questions: 65 (multiple choice, multiple response)
Passing score: 720/1000
Cost: $150 USD
Valid for: 3 years

Domain weights:

Domain	Weight
Design Secure Architectures	30%
Design Resilient Architectures	26%
Design High-Performing Architectures	24%
Design Cost-Optimized Architectures	20%

AWS Global Infrastructure

Regions

Physical geographic areas with AWS data centers. 30+ worldwide.

Key regions: us-east-1 (Virginia — most services, lowest cost), ap-northeast-2 (Seoul), eu-west-1 (Ireland).

Region selection criteria: Data residency (legal requirements), latency, service availability, pricing.

Availability Zones (AZs)

Clusters of one or more discrete data centers within a region. Typically 3–4 per region.

Key principle: High-availability architectures deploy across at least 2 AZs. If one AZ fails, the other(s) continue serving traffic. This is AWS’s core availability pattern.

Edge Locations

Used by CloudFront CDN and Route 53. 400+ worldwide — more than regions, closer to users.

User → Nearest Edge Location → (cache hit) → Response
                             → (cache miss) → Origin → Cache → Response

Cloud Computing Models

Deployment Models

Public cloud: AWS, Azure, GCP — shared infrastructure
Private cloud: Dedicated enterprise data center
Hybrid: Public + private combined

Service Models

Model	Customer manages	Examples
IaaS	OS, middleware, data, apps	EC2, S3
PaaS	Data and apps only	Elastic Beanstalk, RDS
SaaS	App configuration only	Gmail, Salesforce

AWS Shared Responsibility Model

AWS responsibility (“Security OF the cloud”): Physical infrastructure, hardware, network, virtualization layer.

Customer responsibility (“Security IN the cloud”): OS patches, application security, data encryption, network configuration, IAM management.

Customer: "My data, my app, my OS, my network config = my responsibility"
AWS:      "Data centers, servers, storage, networking hardware = our responsibility"

AWS Well-Architected Framework — 6 Pillars

Operational Excellence: Automate operations, make small changes, iterate
Security: Security at every layer, principle of least privilege
Reliability: Automatic failure recovery, horizontal scaling
Performance Efficiency: Right resource types, serverless where applicable
Cost Optimization: Eliminate waste, analyze usage
Sustainability: Minimize energy consumption

Key Concept Cards

Region vs AZ vs Edge ★★★★★ : Region=geographic area (Seoul), AZ=data center cluster (2a/2b/2c), Edge=CDN cache node. HA=minimum 2 AZ deployment.

Shared Responsibility Model ★★★★★ : AWS=infrastructure security, Customer=data/app/OS/network security. One of the exam’s most-tested concepts.

6 Pillars ★★★★☆ : Operational Excellence, Security, Reliability, Performance Efficiency, Cost Optimization, Sustainability. The framework for all architectural decisions.

Practice Quiz

Q1. A Korean web application must keep all user data within South Korea for legal compliance. Which region should you use?

ap-northeast-2 (Seoul Region). AWS guarantees that data stored in a region does not leave that region unless you explicitly configure cross-region replication. Data residency requirements are the highest-priority factor in region selection.

Q2. Who is responsible for patching the operating system on an EC2 instance — AWS or the customer?

The customer. EC2 is an IaaS service. AWS manages the physical host and hypervisor, but the operating system running on the EC2 instance is the customer’s responsibility to patch and maintain. Contrast with managed services like RDS, where AWS handles the database engine patching.

Ch1. AWS SAA Exam Overview and Global Infrastructure