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SAA-C03 · domain

Design Cost-Optimized Architectures

This domain covers selecting and tuning AWS services to minimize spend while meeting performance and availability needs. Questions present a workload description and ask for the cheapest option that still satisfies the stated requirements, so you must weigh pricing models, storage classes, data transfer paths, and capacity commitments against the constraints given.

28 questions4 easy16 medium8 hard

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What this domain covers

What to know about Design Cost-Optimized Architectures

Be able to read a workload description and pick the lowest-cost AWS architecture that still meets its availability, latency, and durability constraints. The single most important thing is matching the pricing model or service tier to the workload's actual usage pattern.

Choosing S3 Gateway VPC endpoints to avoid NAT gateway and public internet data transfer charges

Matching EC2 purchasing options (Spot, Reserved, Savings Plans) to interruptible or steady workloads

Selecting Lambda for sporadic, short API calls instead of always-on compute

Applying RDS Reserved Instances and Aurora Serverless to variable or predictable database traffic

Watch out for

Common Design Cost-Optimized Architectures exam traps

  • ▸Assuming NAT Gateway is required for private subnet access to S3, when a Gateway VPC endpoint is free and keeps traffic off the internet
  • ▸Picking On-Demand or Spot for a steady 24/7 database or server workload where Reserved Instances or Savings Plans cut cost more
  • ▸Overlooking S3 lifecycle transitions to Infrequent Access, Glacier, or Intelligent-Tiering for aging log and backup data

Question index

All Design Cost-Optimized Architectures questions (28)

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1

Refer to the exhibit. An S3 bucket contains millions of small log files. The requirements state that data must be moved to a cheaper storage class after 30 days. The exhibit shows a lifecycle policy. Why might this configuration be sub-optimal for cost?

Hard
2

A company has several AWS accounts and wants to take advantage of Savings Plans to reduce their overall compute spend. They have a mix of EC2 instances, AWS Lambda, and AWS Fargate across multiple regions. Which Savings Plan type will provide the most flexibility and cover all these services?

Hard
3

Refer to the exhibit. An administrator runs a script to identify underutilized EC2 instances. The output shows a production instance that has been running for 30 days. Which action would most effectively reduce costs while maintaining application stability?

Medium
4

A solutions architect is reviewing the architecture of a large VPC. Currently, thousands of EC2 instances in private subnets transfer several terabytes of data daily to Amazon S3 through a NAT Gateway. The NAT Gateway costs have become prohibitively high. Which TWO changes will reduce these costs?

Hard
5

An organization wants to identify and eliminate waste in their AWS account. They are specifically looking for idle resources that are still incurring charges. Which THREE AWS tools or features can help identify these cost-optimization opportunities?

Hard
6

A company is migrating a legacy application to AWS. The application requires a relational database with very infrequent and unpredictable usage—sometimes it is not used for days, and then it sees a burst of activity for an hour. Which database configuration is most cost-effective?

Medium
7

A company is using Amazon EBS volumes for their EC2 instances. The current volumes are General Purpose SSD (gp2). The company wants to reduce costs without losing performance, and in some cases, they need more control over IOPS without increasing storage size. Which TWO steps should they take?

Medium
8

Refer to the exhibit. A junior cloud financial analyst needs to monitor and optimize costs across the organization's AWS account. The analyst requires the ability to view historical cost data and check how effectively Reserved Instances and Savings Plans are being used. Which AWS service is the analyst most likely using with this IAM policy?

Medium
9

A company is designing a global application. They need to replicate 1 TB of data monthly between two AWS Regions. What is the most cost-effective way to minimize data transfer costs?

Medium
10

A company is running an Amazon RDS for MySQL database that experiences predictable, steady traffic during business hours and very low traffic at night. They want to reduce costs without compromising performance. Which TWO steps should the architect take? (Select TWO.)

Hard
11

A solutions architect is designing an application that stores user-uploaded images in Amazon S3. The images are accessed frequently for the first 30 days, then rarely accessed thereafter. Which storage class transition strategy is the most cost-effective?

Medium
12

A financial services company needs to store millions of small records for 7 years to meet regulatory requirements. The records are rarely accessed after the first 30 days. The company wants to minimize storage costs while maintaining the ability to retrieve any record within a few minutes if an audit occurs. Which solution is best?

Medium
13

A company is running a development environment on Amazon RDS for MySQL. The environment is only used by developers during business hours (09:00 to 17:00, Monday through Friday). The company wants to minimize costs for these database instances. Which TWO actions should the company take?

Medium
14

A solutions architect is tasked with reducing the cost of Amazon EBS volumes across a large AWS environment. Which THREE strategies will lead to lower EBS costs? (Select THREE.)

Hard
15

A company is running a large-scale batch processing job that can be interrupted and resumed without loss of data. The job runs for several hours every weekend. Which instance purchasing option will provide the highest cost savings?

Easy
16

A company is migrating a high-traffic web application to AWS. The application uses an Amazon RDS for MySQL database. The database experience high read pressure during business hours, but write activity remains consistent and low. Which TWO architectural changes will reduce costs while maintaining performance? (Select TWO.)

Hard
17

A company has a stable, predictable workload consisting of several Amazon EC2 instances, AWS Lambda functions, and AWS Fargate containers that run 24/7. The company wants to minimize compute costs over a three-year period with minimal administrative effort. Which AWS pricing model should the company choose?

Easy
18

A solutions architect is designing a system for batch processing of large image files. The process can be interrupted and resumed later without loss of data. The workload is expected to run for several hours each night. Which EC2 instance purchasing option will provide the lowest cost?

Easy
19

A data analytics company uses Amazon Redshift for complex queries. The workload is mostly consistent but experiences heavy spikes during the last three days of every month. What is the most cost-effective way to handle these spikes?

Hard
20

An application has an unpredictable workload where it receives bursts of traffic for 5 minutes every few hours, followed by periods of complete inactivity. The application is currently running on a small EC2 instance. Which migration strategy would minimize costs for this specific workload?

Medium
21

A company hosts a batch processing application on Amazon EC2 instances that process large datasets during business hours. The jobs are interruptible and can resume from the last checkpoint if terminated. Which strategy provides the most cost-effective solution?

Medium
22

A company is launching a new application with a DynamoDB backend. They expect the traffic to be highly unpredictable, with sudden spikes and long periods of inactivity. Which capacity mode is the most cost-effective?

Medium
23

A company has a data lake on Amazon S3 where files are uploaded frequently. The access patterns for these files are unpredictable; some are accessed multiple times a day for a week, while others are never accessed again. The company needs to reduce storage costs without manual intervention or performance impact. Which storage strategy is most cost-effective?

Medium
24

An application processes data in bursts, running for 30 seconds every few minutes. The workload is unpredictable. Which compute service offers the most cost-effective solution?

Medium
25

A company has several VPCs in a single region that need to access an S3 bucket for data processing. Currently, traffic goes through a NAT Gateway in each VPC. What is the most cost-effective way to provide access to S3?

Medium
26

A company has several VPCs in the same region that need to access an Amazon S3 bucket for data logging. Currently, data is transferred over the public internet, incurring data transfer charges. What is the most cost-effective way to allow the VPCs to access S3?

Easy
27

A solutions architect is designing a batch processing workload that runs for 4 hours every night. The workload can be interrupted and resumed without data loss. Cost optimization is a primary requirement for this deployment.

Medium
28

A startup is launching a new application with a microservices architecture. One specific service is an API that is only called a few dozen times per day. The execution time is always under 10 seconds. Which compute service would be the most cost-effective for this microservice?

Medium

Frequently asked questions

What does the Design Cost-Optimized Architectures domain cover on the SAA-C03 exam?
Be able to read a workload description and pick the lowest-cost AWS architecture that still meets its availability, latency, and durability constraints. The single most important thing is matching the pricing model or service tier to the workload's actual usage pattern.
How many questions are in this domain?
This page lists all 28 Design Cost-Optimized Architectures questions in the SAA-C03 question bank. The actual exam draws from this domain proportionally to its weighting in the official exam blueprint.
What is the best way to practise this domain?
Start with a short focused session (10 questions) to identify gaps, then work through explanations. Repeat with a longer session once the weak areas feel solid.
Can I practise only Design Cost-Optimized Architectures questions?
Yes — the session launcher on this page filters questions to this domain only. Choose any session length for inline explanations and scoring.
AWS Certified Solutions Architect - Associate SAA-C03 Design Cost-Optimized Architectures Practice Questions