SAA-C03 domain

Design Cost-Optimized Architectures

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189 questions

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What the exam tests

What to know about Design Cost-Optimized Architectures

QoS questions usually test traffic classification (DSCP/CoS), queuing strategies, policing vs shaping and where each mechanism is applied.

DSCP and CoS marking and trust boundaries.

Queuing mechanisms: FIFO, WFQ, CBWFQ, LLQ.

Policing (drops excess) vs shaping (delays excess).

Where QoS is applied: ingress, egress, LAN, WAN.

Question index

All Design Cost-Optimized Architectures questions (189)

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1

You store application logs in an S3 bucket. After 30 days, the logs are rarely accessed, but you must retain them for 1 year for compliance. Which S3 feature is the best way to reduce storage cost while meeting the retention requirement?

2

CloudWatch metrics show your EC2 instances have average CPU utilization around 10% with stable performance over several weeks. The application does not require additional headroom right now. What is the most effective cost-optimization action?

3

A marketing site serves versioned JavaScript and CSS files from Amazon S3 through CloudFront. The origin bill is rising because CloudFront keeps fetching the same files too often, and the application never changes a file at the same URL once it is published. Which two changes should you make? Select two.

4

An application serves static images through Amazon CloudFront. The team observes higher-than-expected origin fetches, which increases origin bandwidth costs. Which change most directly improves CloudFront cache reuse to reduce origin requests for the static content?

5

Your team runs a batch processing workload on EC2 that can tolerate interruptions. If an instance is terminated, the job can restart from checkpoints. To reduce compute costs, what is the most cost-optimized approach?

6

An internal rendering job runs on EC2 workers in an Auto Scaling group. Each job writes checkpoints every few minutes to S3 and can resume from the latest checkpoint after an interruption. The queue depth varies sharply, and the team wants the lowest possible compute cost. Which two changes should they make? Select two.

7

A company has a steady, predictable workload that must run continuously (24/7) in a single AWS Region. The team wants the lowest cost option available for this steady usage, but also expects they may choose different EC2 instance families in the future (without re-buying compute discounts). Which AWS purchase option best meets these goals?

8

Match each data-retention scenario to the most cost-effective Amazon S3 storage class. Assume the retrieval pattern and access-latency requirement are the most important constraints.

9

A web service runs continuously on AWS 24/7. The team expects steady compute usage for the next 12–24 months, but may change instance families/sizes as performance tuning continues. Which purchase option best reduces cost while keeping flexibility to change instance types?

10

Match each workload to the AWS pricing option that most directly minimizes cost while still meeting the stated flexibility requirements. Use each option once.

11

A team stores application logs in Amazon S3. They need access to the logs only occasionally for troubleshooting (infrequent access), and they want to reduce storage cost automatically over time without manually moving objects. What should they implement?

12

Your global users access static images stored in S3. Origin bandwidth costs are higher than expected because CloudFront is not caching effectively. What change most directly reduces origin fetches (and typically lowers data transfer costs) without changing application logic?

13

Match each workload to the most cost-effective compute model or service choice. Focus on how often the workload runs, whether it is interruption-tolerant, and how much administration the team wants to avoid.

14

A service in private subnets downloads product images from Amazon S3 and stores job state in DynamoDB. A NAT Gateway is currently the only route to AWS services, and the monthly bill is dominated by NAT data processing charges. Which two changes will most directly reduce that cost? Select two.

15

Match each private-networking or content-delivery scenario to the AWS feature that most directly reduces cost while meeting the connectivity requirement.

16

You need to run batch jobs on EC2. The jobs can tolerate interruptions: if an instance is terminated, the job can restart from checkpoints. To reduce compute cost as much as possible, what is the best choice?

17

A containerized service runs in private subnets and retrieves secrets from AWS Secrets Manager and configuration parameters from AWS Systems Manager Parameter Store on startup. A NAT Gateway is currently used only for these AWS API calls, and the security team wants to eliminate that recurring charge. Which two endpoints should be added? Select two.

18

A line-of-business application runs on EC2 instances 24/7 with predictable usage for the next year. The application will stay in the same Region, and the team does not want to manage capacity interruptions. Which two purchase options can reduce cost compared with pure On-Demand pricing? Select two.

19

A compliance archive writes one log file per day to Amazon S3. The logs are almost never accessed after day 30, but if they are needed they must still be retrievable in milliseconds. They must be deleted automatically after one year. Which two lifecycle settings should you apply? Select two.

20

A workload runs in private subnets. It must access AWS services such as Amazon S3, but the company wants to avoid using a NAT Gateway to reduce outbound networking costs. What is the best solution?

21

An application stores user-uploaded binaries in S3. Access is unpredictable for the first month, then most objects become cold. The team wants the cheapest approach that avoids manually guessing access patterns. Which two actions are best? Select two.

22

A photo studio stores original project archives in Amazon S3. Objects are read heavily for 14 days after upload, occasionally during the next 11 months, and almost never after one year. The team wants the lowest storage cost while keeping retrieval within minutes during the first year. Which three actions are best? Select three.

23

A media company runs a 24/7 ingestion API on EC2 behind an Application Load Balancer and a nightly transcoding job that can resume from checkpoints. The API fleet runs at roughly 65 percent CPU all day, while the batch workers sit idle most of the time. The company wants to cut compute cost without risking the API. Which two changes should they make? Select two.

24

A company processes product-image uploads in bursts. Each transform takes up to ten minutes, and every job can be retried safely from the beginning. The current EC2 worker fleet is idle most of the day. Which two changes most reduce cost and idle capacity? Select two.

25

A product catalog system uses a relational database for orders and a simple key-value profile store for shopping carts. Traffic is unpredictable, and the company wants to avoid paying for large idle database instances. Which two choices are best? Select two.

26

A SaaS vendor has a steady 24/7 control plane on ECS and several small event-driven tasks that currently run on a separate always-on service. Management wants the billing discount that applies across both ECS and Lambda usage without committing to a specific instance family. Which two actions are best? Select two.

27

A startup has three sandbox accounts and one production account. The CTO wants lower cost and operational overhead while keeping central purchasing and spend visibility. Which two actions are best? Select two.

28

A retailer runs a reporting-heavy relational app on Amazon RDS MySQL. Peak dashboard traffic lasts only three hours each day, but the database is sized for the peak all day. The business wants lower cost without rewriting the application. Which three actions are best? Select three.

29

Multiple teams share one AWS Organization. Finance wants chargeback by project, alerts before overspend, and monthly views by account without manually opening each account. Which three actions best fit? Select three.

30

A fleet of test servers is rebuilt every week from AMIs. EBS volumes are often left behind after termination, and the team creates daily snapshots of every volume even when nothing changes. Which three actions most reduce storage cost while preserving recovery options? Select three.

31

An application runs on EC2 in us-east-1 and frequently reads objects from an S3 bucket that is physically located in us-west-2. The finance team reports unexpectedly high inter-Region data transfer charges because the application retrieves objects for many user requests. A constraint: the bucket in us-west-2 must remain the system of record for compliance, but the application can read from a replica in us-east-1. What should the solutions architect do to minimize network spend while meeting the compliance constraint?

32

A SaaS company uses an S3 bucket for database backups created daily. Backups are rarely restored; the company’s documented RTO is 24 hours, and the compliance policy requires backups be kept for 90 days. The team currently stores all backups in S3 Standard, which is costly. Which single lifecycle policy change is most cost-optimized while still meeting the 24-hour RTO and 90-day retention?

33

A media company runs a batch job that processes image thumbnails. The job can be restarted from checkpoints and does not have user-facing SLAs. The batch capacity can tolerate interruptions. Which EC2 purchasing option is the best cost optimization choice?

34

A data engineering team runs a nightly ETL job on EC2. The job can be checkpointed every 5 minutes and can be retried from the last checkpoint if the instance terminates. The job runtime varies from 2 to 4 hours, and the team has no need for a specific instance type, as long as it completes before 7:00 AM local time. They currently run the job on On-Demand EC2, leading to high monthly compute cost. Which change best reduces cost while maintaining the business deadline?

35

A startup has a stable production web service that runs continuously (24/7) on AWS. They have consistent compute requirements for the next 1 year, but the instance size and family might change as they optimize performance. To reduce cost while maintaining flexibility across instance types, which purchasing option should they consider?

36

A company stores compliance reports in Amazon S3. Objects are written once and rarely accessed. They need to keep the data for 3 years. When retrieval is needed for an audit, the reports can be restored within hours (not minutes). What storage class should the company use for new objects, assuming minimal operational overhead?

37

A marketing team runs a report-generation process that must execute once per day at 02:00 UTC. It usually completes in 10315 minutes, but sometimes takes up to 45 minutes due to varying data volumes. They currently run the workload on an EC2 instance that is always on, which wastes money during off-hours. The team wants to minimize operational overhead and pay mainly for actual execution time. What is the best architecture choice?

38

A company keeps daily database backups in an S3 bucket. They may restore from backups during the first 30 days if there is an issue. After 30 days, backups are rarely restored, but must be retained for 2 years. Which lifecycle strategy most cost-effectively meets these requirements?

39

A media company runs a 24/7 recommendation engine on EC2 in one AWS Region. The workload is interruption-intolerant, and the team expects steady usage but may change instance families and sizes during planned optimizations. Compared to the current On-Demand setup, they want the lowest cost while avoiding the rigidity of locking to a specific instance type. What should the solutions architect recommend?

40

An internal team runs a report-generation job once per day. It typically finishes in a few minutes, and even on its slowest days it still completes in under 15 minutes. The team wants to reduce operational overhead and pay primarily for actual runtime instead of keeping servers running 24/7. Which AWS approach best matches these goals?

41

A startup runs two EC2-based workloads in the same AWS Region. Its customer-facing API is always on, and its nightly video transcoding fleet can restart jobs from checkpoints if an instance is interrupted. The finance team wants the lowest monthly compute cost without changing the application design. Which two actions should the team take? Select two.

42

A team runs an Amazon NLB in a VPC with targets registered in multiple Availability Zones (AZs). Their bill shows high inter-AZ data transfer charges. They want to reduce unnecessary cross-AZ traffic costs while still maintaining healthy targets per AZ. What change is most likely to reduce inter-AZ charges?

43

A company stores application logs in an S3 bucket. They retain logs for 180 days. Compliance requires that the logs be immutable once written, but the business only reviews logs about once per month. Currently, the team stores everything in S3 Standard, and their monthly S3 bill is too high. They want to reduce storage cost without changing the requirement to keep logs for 180 days. Which lifecycle approach best meets the goal?

44

A marketing team runs a report-generation process that must execute once per day at 02:00 UTC. It usually completes in 10315 minutes, but sometimes takes up to 45 minutes due to varying data volumes. They currently run the workload on an EC2 instance that is always on, which wastes money during off-hours. The team wants to minimize operational overhead and pay mainly for actual execution time. What is the best architecture choice?

45

A startup runs two EC2-based workloads in the same AWS Region. Its customer-facing API is always on, and its nightly video transcoding fleet can restart jobs from checkpoints if an instance is interrupted. The finance team wants the lowest monthly compute cost without changing the application design. Which two actions should the team take? Select two.

46

A team runs an Amazon NLB in a VPC with targets registered in multiple Availability Zones (AZs). Their bill shows high inter-AZ data transfer charges. They want to reduce unnecessary cross-AZ traffic costs while still maintaining healthy targets per AZ. What change is most likely to reduce inter-AZ charges?

47

A company keeps daily database backups in an S3 bucket. They may restore from backups during the first 30 days if there is an issue. After 30 days, backups are rarely restored, but must be retained for 2 years. Which lifecycle strategy most cost-effectively meets these requirements?

48

A startup has a stable production web service that runs continuously (24/7) on AWS. They have consistent compute requirements for the next 1 year, but the instance size and family might change as they optimize performance. To reduce cost while maintaining flexibility across instance types, which purchasing option should they consider?

49

A company stores compliance reports in Amazon S3. Objects are written once and rarely accessed. They need to keep the data for 3 years. When retrieval is needed for an audit, the reports can be restored within hours (not minutes). What storage class should the company use for new objects, assuming minimal operational overhead?

50

An application runs on EC2 in us-east-1 and frequently reads objects from an S3 bucket that is physically located in us-west-2. The finance team reports unexpectedly high inter-Region data transfer charges because the application retrieves objects for many user requests. A constraint: the bucket in us-west-2 must remain the system of record for compliance, but the application can read from a replica in us-east-1. What should the solutions architect do to minimize network spend while meeting the compliance constraint?

51

A SaaS company uses an S3 bucket for database backups created daily. Backups are rarely restored; the company’s documented RTO is 24 hours, and the compliance policy requires backups be kept for 90 days. The team currently stores all backups in S3 Standard, which is costly. Which single lifecycle policy change is most cost-optimized while still meeting the 24-hour RTO and 90-day retention?

52

A data engineering team runs a nightly ETL job on EC2. The job can be checkpointed every 5 minutes and can be retried from the last checkpoint if the instance terminates. The job runtime varies from 2 to 4 hours, and the team has no need for a specific instance type, as long as it completes before 7:00 AM local time. They currently run the job on On-Demand EC2, leading to high monthly compute cost. Which change best reduces cost while maintaining the business deadline?

53

A company stores application logs in an S3 bucket. They retain logs for 180 days. Compliance requires that the logs be immutable once written, but the business only reviews logs about once per month. Currently, the team stores everything in S3 Standard, and their monthly S3 bill is too high. They want to reduce storage cost without changing the requirement to keep logs for 180 days. Which lifecycle approach best meets the goal?

54

A media company runs a 24/7 recommendation engine on EC2 in one AWS Region. The workload is interruption-intolerant, and the team expects steady usage but may change instance families and sizes during planned optimizations. Compared to the current On-Demand setup, they want the lowest cost while avoiding the rigidity of locking to a specific instance type. What should the solutions architect recommend?

55

A media company runs a batch job that processes image thumbnails. The job can be restarted from checkpoints and does not have user-facing SLAs. The batch capacity can tolerate interruptions. Which EC2 purchasing option is the best cost optimization choice?

56

An internal team runs a report-generation job once per day. It typically finishes in a few minutes, and even on its slowest days it still completes in under 15 minutes. The team wants to reduce operational overhead and pay primarily for actual runtime instead of keeping servers running 24/7. Which AWS approach best matches these goals?

57

A company processes product-image uploads in bursts. Each transform takes up to ten minutes, and every job can be retried safely from the beginning. The current EC2 worker fleet is idle most of the day. Which two changes most reduce cost and idle capacity? Select two.

58

A photo studio stores original project archives in Amazon S3. Objects are read heavily for 14 days after upload, occasionally during the next 11 months, and almost never after one year. The team wants the lowest storage cost while keeping retrieval within minutes during the first year. Which three actions are best? Select three.

59

A SaaS vendor has a steady 24/7 control plane on ECS and several small event-driven tasks that currently run on a separate always-on service. Management wants the billing discount that applies across both ECS and Lambda usage without committing to a specific instance family. Which two actions are best? Select two.

60

Multiple teams share one AWS Organization. Finance wants chargeback by project, alerts before overspend, and monthly views by account without manually opening each account. Which three actions best fit? Select three.

61

A media company runs a 24/7 ingestion API on EC2 behind an Application Load Balancer and a nightly transcoding job that can resume from checkpoints. The API fleet runs at roughly 65 percent CPU all day, while the batch workers sit idle most of the time. The company wants to cut compute cost without risking the API. Which two changes should they make? Select two.

62

A product catalog system uses a relational database for orders and a simple key-value profile store for shopping carts. Traffic is unpredictable, and the company wants to avoid paying for large idle database instances. Which two choices are best? Select two.

63

An application stores user-uploaded binaries in S3. Access is unpredictable for the first month, then most objects become cold. The team wants the cheapest approach that avoids manually guessing access patterns. Which two actions are best? Select two.

64

A retailer runs a reporting-heavy relational app on Amazon RDS MySQL. Peak dashboard traffic lasts only three hours each day, but the database is sized for the peak all day. The business wants lower cost without rewriting the application. Which three actions are best? Select three.

65

A fleet of test servers is rebuilt every week from AMIs. EBS volumes are often left behind after termination, and the team creates daily snapshots of every volume even when nothing changes. Which three actions most reduce storage cost while preserving recovery options? Select three.

66

A startup has three sandbox accounts and one production account. The CTO wants lower cost and operational overhead while keeping central purchasing and spend visibility. Which two actions are best? Select two.

67

A team serves static content (JavaScript, CSS, images) from S3 through CloudFront. After a recent release, CloudFront reports a low cache hit ratio and the S3 origin receives a much higher request rate. The site still works, but billing shows higher origin and data transfer costs. Which change is most likely to improve cache hit ratio and reduce origin load?

68

A company runs an application on EC2 instances in private subnets. The instances must access Amazon S3, and the team currently routes all outbound traffic to the internet through a NAT Gateway. Monthly NAT Gateway charges increased significantly, even though the application only needs to call S3 (not access other public internet services). Which change will most directly reduce NAT Gateway charges while keeping S3 access working?

69

A media processing pipeline runs batch jobs on EC2. The jobs can tolerate interruptions because they checkpoint progress to durable storage and can restart. The total workload is variable week-to-week, and there is no need to guarantee capacity at specific times. To reduce compute cost while maintaining correctness, what EC2 purchase option and approach is the best fit?

70

A development team expects their EC2 utilization to average about 40% of capacity across the next year. They want to lower costs but need flexibility to change instance families and sizes as requirements evolve (for example, moving from compute-optimized to memory-optimized instances). Which AWS purchasing commitment best meets the goal of reducing cost while keeping flexibility?

71

An S3 bucket stores user-uploaded images. Access patterns are unpredictable: some objects are never read again, while others are occasionally retrieved months later. The team wants to reduce storage cost without having to manually track access frequency or run periodic analyses. Which S3 storage and lifecycle approach is the best fit?

72

A batch-processing system runs only during business hours (08:00–18:00 UTC). The jobs are restartable, and the architecture can tolerate occasional interruptions. Which approach minimizes cost while meeting the business-hours constraint?

73

A service runs in private subnets. It must call AWS APIs (for example, S3 and Secrets Manager). The team currently sends all outbound traffic through a NAT Gateway, and NAT charges have become a major cost driver. The workload must not traverse the public internet. What change most directly reduces NAT Gateway cost while maintaining private connectivity to those AWS services?

74

An S3 bucket stores user-uploaded media. Most objects are never read again, but compliance requires keeping them for at least 18 months. Retrieval is rare and typically only needed during investigations. The current design keeps everything in S3 Standard, increasing storage cost. Which configuration best optimizes cost while meeting the retention and rare-access requirements?

75

A static web application uses CloudFront with an S3 origin for assets (JavaScript, CSS, images). After deploying a new frontend build, the CloudFront cache hit ratio dropped significantly because the S3 origin receives many repeated requests for the same assets. The team notices that requests now include the Authorization header in asset requests. Which change is most likely to restore cache efficiency and reduce origin request costs?

76

A latency-sensitive API is implemented with AWS Lambda. The team enabled provisioned concurrency to avoid cold starts, setting provisioned concurrency to 50 because marketing campaigns occasionally cause spikes. However, during most weekdays the API receives little traffic (near zero), and the team is seeing high monthly Lambda costs from idle provisioned capacity. What is the best cost-optimized strategy that still meets the requirement of fast initial responses during traffic spikes?

77

A company stores user uploads in an S3 bucket. Objects are accessed rarely after upload, but when an object is accessed, it must be retrievable quickly (minutes to a few hours). Objects must be retained for at least 18 months. The team wants to reduce storage cost while meeting these requirements. Which lifecycle configuration best fits these requirements?

78

A media processing pipeline runs batch jobs overnight. The jobs are stateless, can be restarted from checkpoints, and can tolerate interruptions. The team wants to minimize compute cost. Which EC2 approach is the best fit?

79

A company runs EC2 workloads in one region with somewhat steady overall demand. Over time, the team frequently changes instance families (for performance/optimization) and sometimes changes instance size, but wants predictable cost discounts. Which purchase option provides the best balance of cost savings and flexibility?

80

An EC2 workload runs in one region on a single instance type. For the last month, CloudWatch metrics show average CPU utilization of 12% and no sustained memory pressure. The team wants to reduce cost while maintaining the current performance level. What is the best first step?

81

A company hosts an application on EC2 instances in private subnets. The instances must (1) read objects from Amazon S3 and (2) retrieve secrets from AWS Secrets Manager. The team currently sends all outbound traffic through a NAT gateway to reach both services. They want to reduce monthly cost while keeping traffic private (no internet egress) and without changing application logic. Which change is the most cost-effective?

82

A media company runs a fleet of EC2 instances using Auto Scaling across multiple instance families (for example, m-series and c-series) in a single region. The business wants to commit to steady usage for one year to reduce cost, but the application team must retain flexibility to switch instance families and scale up/down as demand changes. They need the cost-reduction approach that best matches this flexibility. Which option is the best fit?

83

A video processing pipeline runs batch jobs that are safe to interrupt and restart. The jobs checkpoint progress to durable storage every few minutes, and the team can automatically resubmit from the last checkpoint. They want to minimize compute cost while accepting that capacity can be interrupted. Which launch configuration for the processing workers is the best cost-optimized choice?

84

A team serves static web assets (JS, CSS, images) from an Amazon S3 origin through CloudFront. Recently, the S3 origin has received a high number of requests for the same files, increasing origin data transfer costs. CloudFront access logs show many cache misses, and each request includes a unique query string used only for tracking (for example, ?utm=...). The application does not require query-string-specific content. What CloudFront change will most directly reduce origin fetches and cost?

85

A startup runs a mix of workloads using both EC2 instances and AWS Lambda functions. Over the next 12 months, the team expects the overall level of compute usage to be fairly steady, but they may change EC2 instance types for performance tuning and they may add or remove Lambda functions. They want the lowest-cost commitment that will discount *both* EC2 and Lambda usage without requiring them to commit to a specific EC2 instance family (or a fixed instance type). Which AWS option best meets this requirement?

86

A media company uploads raw video thumbnails to an S3 bucket every hour. The application needs these thumbnails for active browsing for the first 7 days. After day 7, access becomes rare. Requirements: - Objects must remain available in S3 for at least 180 days total. - After day 7, the team can tolerate retrieval latency in the range of minutes to hours. - They want to minimize storage cost while keeping the ability to read objects (no application changes required). Which storage strategy is the most cost-optimized fit?

87

A company serves versioned images from S3 through CloudFront. After a release, CloudFront origin fetches increased sharply and the monthly CloudFront bill went up. They reviewed CloudFront logs and found that many requests include a query string parameter `reqId` that is unique per request (for example, `...?v=2026-04-01&reqId=...`). The team currently forwards all query strings to the cache key. What change is most likely to reduce origin fetches and cost while keeping the versioned images correct?

88

A team runs an EC2-based API on a single Auto Scaling group (ASG). Over the last month, they observed: - Average CPU utilization is ~15%. - p95 latency is stable and within the performance target. - The attached EBS volumes are gp3, provisioned with high baseline IOPS/throughput “just to be safe,” but CloudWatch shows consistently low utilization of those provisioned IOPS/throughput limits. They want to reduce monthly cost while maintaining current performance. Which action is the best cost-optimized choice?

89

An ecommerce company runs a 24/7 frontend tier on EC2 and a nightly image-rendering job that can be interrupted and resumed from checkpoints. They want to minimize monthly compute cost without changing the application architecture. Which two actions should they take? Select two.

90

A media company stores application logs in S3. The logs must be kept for 400 days. They are read heavily for the first 30 days, occasionally for the next 90 days, and almost never after that. Retrieval after the first 3 months can wait a few hours. Which three lifecycle actions should they use to minimize storage cost? Select three.

91

An application runs in private subnets and must access Amazon S3, Amazon DynamoDB, and AWS Secrets Manager. The security team wants the traffic to stay on the AWS network and the finance team wants to eliminate NAT Gateway charges. Which three changes should they make? Select three.

92

A static site is hosted in Amazon S3 and delivered by CloudFront. After a frontend release, the same JavaScript bundles are fetched repeatedly from the origin. Logs show that requests include unneeded query strings and cookies, which prevent cache reuse. Which two changes should the team make to reduce origin traffic and cost? Select two.

93

A public API currently uses API Gateway REST APIs and Lambda. Traffic is low most of the day, but marketing runs a predictable traffic spike every weekday at 09:00 UTC. Users complain about cold starts during the first few minutes of the spike, and the team wants to avoid paying for provisioned concurrency all day. Which two changes should they make? Select two.

94

A development team stores application logs in CloudWatch Logs and has enabled detailed EC2 monitoring on every instance. Auditors only require 90 days of logs, and operations only needs 5-minute instance metrics. Which three changes would most directly reduce recurring monitoring costs while still meeting those requirements? Select three.

95

An application team sees that a fleet of EC2 instances averages 15% CPU utilization and has no memory pressure. The service must keep running continuously, but the team wants to lower cost with minimal risk. Which two actions should they take first? Select two.

96

A company runs an order system on EC2 with a self-managed PostgreSQL database, a self-managed RabbitMQ broker, and a shared file server for attachments. The team wants to reduce patching, backups, and cluster administration while keeping the architecture simple and using managed services where possible. Which three changes should they make? Select three.

97

A startup runs a 24/7 web tier on Amazon EC2 with a stable baseline of 8 instances and a nightly analytics batch job that can resume from checkpoints if interrupted. The company wants to minimize monthly compute cost without hurting the always-on web tier. Which two actions should it take? Select two.

98

A data-processing application runs in private subnets and needs to read objects from Amazon S3 and write items to Amazon DynamoDB. The team currently routes all outbound traffic through a NAT Gateway, and monthly networking charges are rising. Which two changes will most directly reduce cost while keeping traffic on the AWS network? Select two.

99

A media company keeps application logs in Amazon S3 for 400 days. The logs are read heavily for the first 30 days, occasionally for the next 90 days, and almost never after that. The team wants to lower storage cost without affecting retention requirements. Which two lifecycle transitions should it configure? Select two.

100

A global software company distributes large installation packages from an Amazon S3 bucket. During release week, many users in the same region download the same file repeatedly, and the origin bill is rising because the same objects are fetched over and over. The team wants to lower origin data transfer and improve delivery cost. Which two actions should it take? Select two.

101

A marketing site serves versioned JavaScript and CSS files from an Amazon S3 origin through Amazon CloudFront. After a frontend release, the CloudFront cache hit ratio dropped because browsers now send an Authorization header on every static asset request even though the assets are public and do not require authentication. The team wants to lower origin load and improve cache efficiency. Which two actions should it take? Select two.

102

A development team stores application logs in Amazon CloudWatch Logs and has enabled detailed EC2 monitoring on every instance. Auditors require the logs to be retained for 90 days, but the operations team only needs the last 7 days to remain searchable in CloudWatch. Which two actions should they take to reduce monitoring cost? Select two.

103

A company runs a customer portal on self-managed PostgreSQL on EC2, plus a self-managed RabbitMQ cluster for asynchronous work that only requires durable queueing and does not depend on RabbitMQ-specific exchange features. The operations team spends a lot of time patching, backing up, and scaling both systems. The business wants to reduce infrastructure management overhead and total cost of ownership. Which two changes are the best fit? Select two.

104

A serverless checkout API has predictable traffic spikes every weekday at 09:00 UTC and low traffic the rest of the day. The team wants to reduce cost while keeping response times fast during the recurring spike. Which two actions should they take? Select two.

105

Based on the exhibit, your application runs entirely in private subnets and only needs to reach Amazon S3, Amazon DynamoDB, AWS Secrets Manager, and CloudWatch Logs. The monthly bill is dominated by NAT Gateway charges. Which change most directly reduces cost while preserving private connectivity to these AWS services?

106

Based on the exhibit, the team wants to minimize compute cost for a workload with a steady 24/7 baseline and a separate nightly batch job that can be interrupted and resumed from checkpoints. They also expect to change EC2 instance families during the year as performance needs evolve. Which approach is the best fit?

107

Based on the exhibit, the company stores application logs in Amazon S3 for 400 days. The logs are read heavily for the first 30 days, occasionally for the next 90 days, and very rarely after that. Retrieval after day 120 can take up to several hours, but the data must remain available until day 400. Which lifecycle policy is the most cost-effective fit?

108

Based on the exhibit, the team serves versioned JavaScript and CSS files from an S3 origin through CloudFront. After a release, the cache hit ratio dropped and origin fetches increased sharply. What change best reduces both CloudFront and S3 costs without changing the application’s public behavior?

109

Based on the exhibit, the company wants to lower CloudWatch and EC2 monitoring costs. Auditors require logs to be retained for 90 days, but operations only uses detailed per-instance metrics during rare troubleshooting events. Which change best reduces recurring cost while preserving the required visibility?

110

Based on the exhibit, the company runs a self-managed RabbitMQ cluster on EC2 for asynchronous work. The queue only needs durable at-least-once delivery, and the application does not require AMQP-specific features such as exchanges, routing keys, or broker plugins. Which change is the best cost-optimization move?

111

A company runs Amazon EC2 instances in private subnets. Those instances only need to access Amazon S3 (read/write) and Amazon DynamoDB. The VPC currently routes all outbound traffic through a NAT Gateway, increasing monthly cost. What change most directly reduces NAT Gateway usage for these AWS services?

112

An S3 bucket stores application logs. After 30 days, the team rarely accesses the logs, but compliance requires keeping them for 18 months. Which setup most directly reduces storage cost while maintaining compliance?

113

A startup expects steady compute usage around the clock for the next year. They want to reduce costs compared to On-Demand pricing, without tightly planning specific instance types. Which option best matches their goal?

114

An application runs on an EC2 Auto Scaling group. Over the last month, CPU utilization averaged 8% with no sustained memory pressure, and response times are stable. The team wants to lower monthly cost without changing the application. What is the most appropriate next step for cost optimization?

115

A team stores application logs in Amazon CloudWatch Logs. They enabled long retention and detailed dashboards, resulting in higher-than-expected monthly spend. Compliance requires retaining logs for 90 days, but operations only needs aggregated views. Which change most directly reduces CloudWatch Logs cost while meeting the requirement?

116

A website serves versioned JavaScript and CSS files through CloudFront, but origin fetches are still high and the CloudFront bill increased. Developers confirm that URLs include a version in the filename (for example, app.1.4.2.js). What CloudFront behavior/configuration is most likely to reduce origin fetches and associated costs?

117

A SaaS company runs a production API on an EC2 Auto Scaling group with steady demand 24/7. The team uses multiple instance types over time (they switch types during tuning) but the overall compute hours are stable. They want a cost reduction without committing to a specific instance type or size. Which AWS pricing option best meets the requirement?

118

A team stores application logs in an S3 bucket. They keep logs for 18 months for compliance. Access patterns: logs are heavily accessed during the first 30 days, rarely accessed between days 31 and 180, and almost never accessed after day 180. They currently store everything in S3 Standard and want to reduce storage cost without violating the 18-month retention requirement. What should they implement?

119

A static marketing site is served through CloudFront from an S3 origin. After a product update, customers report a drop in CloudFront cache hit ratio and the CloudFront bill increases because the origin is receiving many more requests for the same JS/CSS assets. Asset URLs are versioned, but requests now include an Authorization header even though these assets are public. Which CloudFront change most directly improves the cache hit ratio for these assets?

120

A media company runs a nightly batch job that processes video thumbnails. The batch can be interrupted at any time, and workers can resume automatically from checkpoints (a termination does not corrupt progress). The business goal is the lowest possible compute cost, and occasional interruptions are acceptable as long as the job continues automatically. Which approach is most cost-optimized?

121

An Auto Scaling group for a background worker runs EC2 instances continuously. Over the last 30 days, CloudWatch shows sustained CPU utilization around 6% with no memory pressure, and queue processing latency meets all SLAs. The team wants to lower monthly cost with minimal risk. What is the best next action?

122

A company hosts application servers in private subnets. They must access Amazon S3 and read secrets from AWS Secrets Manager, but they want to avoid internet egress. They currently use a NAT gateway and see high NAT-related costs. What change most directly reduces cost while keeping traffic on the AWS network?

123

A team runs an EC2-based service and ships logs to Amazon CloudWatch Logs. They enabled long log retention and turned on detailed monitoring to improve troubleshooting. Their monthly CloudWatch costs have grown unexpectedly. Compliance requires that the logs remain available in CloudWatch Logs (for querying and audits) for 90 days, and alerts/alarms do not require detailed EC2 monitoring. What change best reduces cost while meeting requirements?

124

A batch analytics job runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost?

125

A production internal reporting portal runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy?

126

A test environment stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost?

127

A media processing workflow in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost?

128

A dev sandbox has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity?

129

A log archive has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances?

130

A marketing site runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost?

131

A risk simulation workload uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured?

132

A batch analytics job currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first?

133

A internal reporting portal serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit?

134

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations?

135

A media processing workflow generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used?

136

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost?

137

A production log archive runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy?

138

A marketing site stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost?

139

A risk simulation workload in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost?

140

A batch analytics job has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity?

141

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances?

142

A test environment runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost?

143

A media processing workflow uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured?

144

A dev sandbox currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first?

145

A log archive serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit?

146

A marketing site has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations?

147

A risk simulation workload generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used?

148

A batch analytics job runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The design must avoid adding custom operational scripts.

149

A production internal reporting portal runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The design must avoid adding custom operational scripts.

150

A test environment stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost? The design must avoid adding custom operational scripts.

151

A media processing workflow in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The design must avoid adding custom operational scripts.

152

A dev sandbox has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity? The design must avoid adding custom operational scripts.

153

A log archive has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The design must avoid adding custom operational scripts.

154

A marketing site runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost? The design must avoid adding custom operational scripts.

155

A risk simulation workload uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured? The design must avoid adding custom operational scripts.

156

A batch analytics job currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first? The design must avoid adding custom operational scripts.

157

A internal reporting portal serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit? The design must avoid adding custom operational scripts.

158

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The design must avoid adding custom operational scripts.

159

A media processing workflow generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used? The design must avoid adding custom operational scripts.

160

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The design must avoid adding custom operational scripts.

161

A production log archive runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The design must avoid adding custom operational scripts.

162

A marketing site stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost? The design must avoid adding custom operational scripts.

163

A risk simulation workload in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The design must avoid adding custom operational scripts.

164

A batch analytics job has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity? The design must avoid adding custom operational scripts.

165

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The design must avoid adding custom operational scripts.

166

A test environment runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost? The design must avoid adding custom operational scripts.

167

A media processing workflow uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured? The design must avoid adding custom operational scripts.

168

A dev sandbox currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first? The design must avoid adding custom operational scripts.

169

A log archive serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit? The design must avoid adding custom operational scripts.

170

A marketing site has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The design must avoid adding custom operational scripts.

171

A risk simulation workload generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used? The design must avoid adding custom operational scripts.

172

A batch analytics job runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The architecture review board prefers a managed AWS-native control.

173

A production internal reporting portal runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The architecture review board prefers a managed AWS-native control.

174

A test environment stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost? The architecture review board prefers a managed AWS-native control.

175

A media processing workflow in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The architecture review board prefers a managed AWS-native control.

176

A dev sandbox has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity? The architecture review board prefers a managed AWS-native control.

177

A log archive has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The architecture review board prefers a managed AWS-native control.

178

A marketing site runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost? The architecture review board prefers a managed AWS-native control.

179

A risk simulation workload uses CloudWatch Logs heavily. Retaining all debug logs forever is increasing costs. What should be configured? The architecture review board prefers a managed AWS-native control.

180

A batch analytics job currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first? The architecture review board prefers a managed AWS-native control.

181

A internal reporting portal serves infrequently accessed user documents that must be available immediately when requested. Which S3 storage class is likely the best cost fit? The architecture review board prefers a managed AWS-native control.

182

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The architecture review board prefers a managed AWS-native control.

183

A media processing workflow generates analytics files that are accessed unpredictably. Some files become hot again months later. The team wants automatic storage cost optimisation without retrieval delays. What should be used? The architecture review board prefers a managed AWS-native control.

184

A dev sandbox runs for several hours each night and can be interrupted and restarted. Which EC2 purchasing option should minimize cost? The architecture review board prefers a managed AWS-native control.

185

A production log archive runs continuously on EC2 with predictable usage for the next three years. The team wants a discount while retaining some instance-family flexibility. What should they buy? The architecture review board prefers a managed AWS-native control.

186

A marketing site stores logs in S3. Logs are queried for 30 days, rarely accessed for one year, and then retained for compliance. What should reduce storage cost? The architecture review board prefers a managed AWS-native control.

187

A risk simulation workload in private subnets downloads large amounts of data from S3 through a NAT gateway. NAT data processing charges are high. What should the architect use to reduce cost? The architecture review board prefers a managed AWS-native control.

188

A batch analytics job has unpredictable DynamoDB traffic with long idle periods and occasional spikes. Which capacity mode should minimize operational overhead and avoid paying for idle provisioned capacity? The architecture review board prefers a managed AWS-native control.

189

A internal reporting portal has old unattached EBS volumes and many stale snapshots. Which two actions reduce storage cost without affecting running instances? The architecture review board prefers a managed AWS-native control.

Watch out for

Common Design Cost-Optimized Architectures exam traps

  • Policing drops traffic; shaping buffers it — they solve different problems.
  • DSCP EF (46) is for voice; AF classes are for data tiers.
  • QoS must be configured end-to-end to be effective.
  • CoS values are Layer 2; DSCP is Layer 3.

Frequently asked questions

What does the Design Cost-Optimized Architectures domain cover on the SAA-C03 exam?
QoS questions usually test traffic classification (DSCP/CoS), queuing strategies, policing vs shaping and where each mechanism is applied.
How many questions are in this domain?
This page lists all 189 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 use the interactive practice page to 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 or try the interactive practice page for inline explanations.