AWS SAA-C03 design cost-optimized architectures syllabus

Design Cost-Optimized Architectures is now the lightest domain at 20 per cent, and it is the one whose weighting fell. At the original SAA-C03 launch it carried 26 per cent, level with security. It has lost six points and security has gained four, so the gap between them is now ten.

Study plans written against the old numbers give this domain roughly a third more time than it earns. The AWS SAA-C03 syllabus hub page covers the other three domains.

Pattern

This domain carries 20 per cent of the scored content. The current weightings are below, and they replace the 26, 24, 24 and 26 split that most study material still quotes.

Task statements

Task 4.1: Design cost-optimised storage solutions

• Storage tiering, including cold tiering for object storage

• Amazon S3 object lifecycles and data lifecycle selection

• Block storage options, including the choice between HDD and SSD volume types

• Storage services and use cases: Amazon FSx, Amazon EFS, Amazon S3 and Amazon EBS

• Backup and archival selection

• Hybrid storage with AWS DataSync, AWS Transfer Family and AWS Storage Gateway

• The lowest cost method of transferring data into AWS storage

• Access options such as an Amazon S3 bucket with Requester Pays

• Right sizing storage, and when storage auto scaling is required

Task 4.2: Design cost-optimised compute solutions

• Purchasing options: Spot Instances, Reserved Instances and Savings Plans

• Instance types, families and sizes, including memory optimised and compute optimised

• Optimising compute utilisation through containers, serverless computing and microservices

• Scaling strategies including auto scaling and EC2 hibernation

• Horizontal against vertical scaling for elastic workloads

• Choosing between AWS Lambda, Amazon EC2 and AWS Fargate on cost

• Load balancer selection on cost grounds between Application, Network and Gateway Load Balancers

• Availability requirements for production against non-production workloads

• Hybrid compute with AWS Outposts, and edge processing

Task 4.3: Design cost-optimised database solutions

• Database type and engine selection on cost, including Amazon DynamoDB against Amazon RDS

• Serverless database options

• Backup and retention policies, including snapshot frequency

• Data retention policies and capacity planning with capacity units

• Caching strategies, database connections and proxies

• Read replicas

• Migrating schemas and data between locations or engines

Task 4.4: Design cost-optimised network architectures

• NAT gateway cost, including NAT instance against NAT gateway, and a single shared gateway against one per Availability Zone

• Network connection choice between AWS Direct Connect, VPN and the public internet

• Routing to minimise data transfer costs, between Regions, between Availability Zones and from private to public

• VPC endpoints and AWS Global Accelerator

• Network topology and peering, including AWS Transit Gateway and VPC peering

• CDN and edge caching for cost rather than for speed

• Throttling strategy, and bandwidth allocation such as Direct Connect speed

All four tasks repeat the same two cost management knowledge points: cost allocation tags with multi account billing, and the tooling of AWS Cost Explorer, AWS Budgets and the AWS Cost and Usage Report. Learning those once covers a quarter of the domain.

Services most used in this domain

• AWS Cost Explorer, AWS Budgets, the AWS Cost and Usage Report and Savings Plans

• Amazon S3 with lifecycle policies and S3 Glacier, Amazon EBS, Amazon EFS and Amazon FSx

• Amazon EC2 with Spot and Reserved Instances, AWS Lambda and AWS Fargate

• AWS Compute Optimizer and AWS Trusted Advisor

• Amazon RDS, Amazon Aurora Serverless and Amazon DynamoDB

• NAT gateways, VPC endpoints, AWS Transit Gateway and AWS Direct Connect

What is not in this domain

• No invoicing, procurement or contract negotiation

• No current pricing figures. Questions concern relative cost rather than dollar amounts

• No performance tuning, which belongs to Domain 3

• No security design, which belongs to Domain 1

How to spend the time

Learn the cost management tooling once. Cost allocation tags, multi account billing, AWS Cost Explorer, AWS Budgets and the Cost and Usage Report appear in all four tasks, so the domain is narrower than its four task statements suggest.

The purchasing options are the highest yield topic. Spot, Reserved Instances and Savings Plans each fit a different workload profile, and scenario questions describe the profile and expect the right one.

Data transfer charges are the cost topic candidates know least. Traffic between Regions, between Availability Zones and out to the internet all cost differently, and VPC endpoints exist partly to avoid some of it.

Give this domain less time than the old weighting implies and move the hours to security. At 20 per cent it is the lightest of the four. Browse the available AWS Solutions Architect practice papers.

Common mistakes

• Preparing this domain at the old 26 per cent weighting

• Learning the cost management tools four times, once per task statement

• Choosing Spot Instances for a workload that cannot tolerate interruption

• Overlooking NAT gateway placement, where one per Availability Zone against one shared is a named cost decision

• Ignoring data transfer charges between Availability Zones

• Answering on performance grounds when the question asks which option is cheapest

• Memorising prices, when questions concern relative cost rather than figures

How the weighting changed

Frequently asked questions

How much of the AWS SAA-C03 exam is cost optimisation?

20 per cent of the scored content, which makes it the lightest of the four domains.

Did this domain used to be worth more?

Yes. At the original SAA-C03 launch it carried 26 per cent. It was reduced to 20 per cent in a revision made under the same exam code.

What are the three purchasing options?

Spot Instances, Reserved Instances and Savings Plans, all named in Task 4.2.

Which cost management tools are examined?

AWS Cost Explorer, AWS Budgets and the AWS Cost and Usage Report, together with cost allocation tags and multi account billing. All four task statements reference them.

Do I need to know AWS prices?

No. Questions concern relative cost between options rather than specific figures.

Is NAT gateway cost really examined?

Yes. The choice between a NAT instance and a NAT gateway, and between one shared gateway and one per Availability Zone, is named in Task 4.4.

Are data transfer charges in scope?

Yes, named under routing to minimise transfer costs between Regions, between Availability Zones and from private to public.

When are Spot Instances the wrong answer?

When the workload cannot tolerate interruption, since Spot capacity can be reclaimed.

How many task statements does this domain have?

Four, which is more than Domain 1 or Domain 2 despite it carrying the least weight.

Is Amazon S3 lifecycle management examined?

Yes, named under storage tiering and data lifecycle selection in Task 4.1.