Courseiva

CCNA Soa Cost Performance Questions

33 questions · Soa Cost Performance topic · All types, answers revealed

Practice these questionsExam hubAll questions
1
MCQeasy

An application runs on c5.xlarge EC2 instances 24 hours a day, 7 days a week in us-east-1. The workload is stable and will not change instance type for at least 12 months. The team wants to reduce compute costs by 30 to 40 percent compared to On-Demand pricing. Which purchasing option achieves this with the lowest financial risk?

A.Purchase a 1-year Standard Reserved Instance for c5.xlarge in us-east-1 with All Upfront or Partial Upfront payment
B.Use Spot Instances with an interruption tolerance of 5 minutes for the workload
C.Enable EC2 Auto Scaling with a target tracking policy to scale down to zero instances during off-peak hours
D.Purchase a 3-year Convertible Reserved Instance to maximize the discount percentage
AnswerA

A 1-year Standard RI matches the 12-month stability horizon and delivers 30–40 percent savings versus On-Demand. All Upfront provides the deepest discount; Partial Upfront reduces the upfront cash requirement with a slightly lower overall saving. The 1-year commitment limits risk compared to a 3-year commitment for an uncertain future period.

Why this answer

A 1-year Standard Reserved Instance (RI) with All Upfront or Partial Upfront payment offers a 30-40% discount over On-Demand pricing for a stable, always-on workload. This option provides the lowest financial risk because it commits to a fixed instance type and region for only one year, matching the workload's stable nature without the flexibility premium of Convertible RIs or the interruption risk of Spot Instances.

Exam trap

The trap here is that candidates may choose the 3-year Convertible RI (Option D) for its higher discount percentage, overlooking the fact that the longer commitment and unnecessary flexibility introduce greater financial risk for a stable, unchanging workload.

How to eliminate wrong answers

Option B is wrong because Spot Instances can be interrupted with as little as a 5-minute warning, which introduces significant financial and operational risk for a workload that must run 24/7 without interruption. Option C is wrong because scaling down to zero instances during off-peak hours would violate the requirement that the application runs 24/7, and it does not address the need to reduce costs for the always-on baseline. Option D is wrong because a 3-year Convertible Reserved Instance, while offering a higher discount percentage, introduces greater financial risk due to the longer commitment period and the unnecessary flexibility to change instance types, which the workload does not require.

Practice this question →
2
MCQmedium

A SysOps administrator notices that the monthly bill for Amazon S3 has increased significantly. The company uses S3 for storing application logs and user uploads. The logs are accessed rarely but must be retained for 3 years. User uploads are accessed frequently for the first 30 days, then rarely after. Which S3 lifecycle policy will optimize storage costs?

A.Transition logs to S3 Glacier Deep Archive after 30 days, and transition user uploads to S3 Standard-IA after 30 days, then to Glacier Deep Archive after 90 days.
B.Transition user uploads to S3 Glacier Deep Archive after 30 days, and transition logs to S3 Glacier after 90 days.
C.Move logs to S3 Glacier Deep Archive after 30 days, and delete user uploads after 1 year.
D.Transition logs to S3 Standard-IA after 30 days, and transition user uploads to S3 One Zone-IA after 30 days.
AnswerA

This is correct because logs are typically append-only and rarely accessed after the first 30 days, making S3 Glacier Deep Archive the lowest-cost storage class while satisfying the 3-year retention requirement. User uploads, however, are frequently accessed in the month after upload, so S3 Standard-IA after 30 days reduces cost without sacrificing retrieval performance; then transitioning to Glacier Deep Archive after 90 days aligns with the access drop-off and keeps lifecycle costs minimal.

Why this answer

This lifecycle policy optimizes costs by transitioning logs (rarely accessed but need retention) directly to S3 Glacier Deep Archive after 30 days, and for user uploads (frequently accessed for the first 30 days, then rarely), transition to S3 Standard-IA after 30 days, then to Glacier Deep Archive after 90 days. Option B is wrong because it transitions user uploads (initially frequent access) to Glacier Deep Archive too early, causing retrieval costs. Option C is wrong because logs should be archived, but deleting user uploads after 1 year may be premature.

Option D is wrong because it transitions logs to Standard-IA, which is not cost-effective for long-term retention, and user uploads to One Zone-IA, which lacks durability.

Practice this question →
3
MCQmedium

A company runs a web application on a fleet of Amazon EC2 instances behind an Application Load Balancer. The application has predictable traffic patterns with high traffic during business hours and low traffic at night. The SysOps administrator wants to reduce compute costs while ensuring the application remains responsive during peak hours. The administrator has already implemented Auto Scaling based on CPU utilization. Which additional action should the administrator take to optimize costs?

A.Use On-Demand instances only
B.Purchase Reserved Instances for the baseline capacity and use Spot Instances for the additional capacity during peak hours
C.Increase the minimum number of instances in the Auto Scaling group
D.Use Dedicated Hosts to reduce licensing costs
AnswerB

This approach minimizes costs by applying the highest discount (Reserved Instances) to the steady-state capacity and leveraging the cost savings of Spot Instances for the flexible, peak-demand capacity. Auto Scaling can be configured to launch Spot Instances as needed, providing both cost efficiency and performance.

Why this answer

It combines Reserved Instances for predictable baseline capacity (lower cost per hour) with Spot Instances for elastic peak demand, leveraging Auto Scaling to handle variable traffic. This hybrid approach reduces compute costs compared to using On-Demand instances for all capacity, while maintaining responsiveness during peak hours.

Exam trap

The trap here is that candidates may think increasing the minimum instance count (Option C) improves responsiveness, but it actually increases costs during low-traffic periods without addressing the cost optimization goal.

How to eliminate wrong answers

Option A is wrong because using only On-Demand instances ignores cost-saving opportunities from Reserved or Spot Instances, leading to higher costs for predictable baseline traffic. Option C is wrong because increasing the minimum number of instances raises baseline costs unnecessarily, as the application has low traffic at night and does not require a higher minimum. Option D is wrong because Dedicated Hosts are designed for licensing or compliance requirements, not for general cost optimization, and they incur additional costs without addressing variable traffic patterns.

Practice this question →
4
MCQhard

A company stores video files in Amazon S3. The files are accessed frequently for the first week, then weekly for the next month, and then rarely after that. The files must be retained for 5 years and any access must be served within minutes. The SysOps administrator needs to minimize storage costs while meeting these requirements. Which lifecycle policy configuration is the most cost-effective?

A.Transition to S3 Standard-IA after 7 days, then to S3 Glacier Flexible Retrieval after 30 days.
B.Transition to S3 One Zone-IA after 7 days, then to S3 Glacier Deep Archive after 30 days.
C.Transition to S3 Standard-IA after 7 days, then to S3 Glacier Instant Retrieval after 30 days.
D.Transition to S3 Intelligent-Tiering after 7 days.
AnswerC

S3 Standard-IA after 7 days is a sound choice because the files are accessed weekly during that period, and Standard-IA offers the same high durability (99.999999999%) and millisecond latency as Standard while reducing storage costs. After 30 days, transitioning to S3 Glacier Instant Retrieval further cuts storage costs while still providing millisecond retrieval times, so the videos remain instantly accessible on demand. This lifecycle meets the 'within minutes' requirement without incurring the higher retrieval latency or costs of Flexible Retrieval or Deep Archive, making it the most cost-effective and compliant strategy.

Why this answer

It transitions to S3 Standard-IA after 7 days (matching the frequent first-week access), then to S3 Glacier Instant Retrieval after 30 days (matching the weekly access for the next month). Glacier Instant Retrieval provides millisecond retrieval for rarely accessed data, meeting the 'within minutes' requirement while minimizing costs compared to Standard-IA or Intelligent-Tiering.

Exam trap

The trap here is that candidates often confuse S3 Glacier Flexible Retrieval or S3 Glacier Deep Archive as cost-effective options without verifying the retrieval time requirement, assuming 'Glacier' always means cheap but slow, while the question explicitly requires access 'within minutes'.

How to eliminate wrong answers

Option A is wrong because S3 Glacier Flexible Retrieval has retrieval times of minutes to hours (not within minutes), failing the access requirement. Option B is wrong because S3 One Zone-IA does not provide the durability needed for long-term retention (5 years) and S3 Glacier Deep Archive has retrieval times of 12-48 hours, violating the 'within minutes' requirement. Option D is wrong because S3 Intelligent-Tiering incurs monitoring and automation costs that are not cost-effective for a predictable access pattern, and it does not transition to a cold storage tier that minimizes costs for rarely accessed data after 30 days.

Practice this question →
5
Drag & Dropmedium

Drag and drop the steps to configure a VPC peering connection between two VPCs into the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

First create the peering request, then accept it, then update route tables in both VPCs, and finally adjust security groups.

Practice this question →
6
MCQhard

A company runs a read-heavy database workload on Amazon RDS for PostgreSQL with a primary instance and two read replicas. The SysOps administrator observes that the read replicas frequently experience high replica lag during peak hours, causing stale reads for the application. The administrator needs to reduce replica lag while optimizing costs. The workload is predictable, with spikes during business hours and low traffic at night. Which combination of actions should the administrator take?

A.Convert the read replicas to Multi-AZ instances to improve the replication process and reduce lag.
B.Upgrade the instance class of the read replicas to a larger type with more CPU and memory to handle the increased WAL replay rate.
C.Add additional read replicas to distribute the read load and reduce the lag on each individual replica.
D.Upgrade the primary DB instance to a larger class with increased IOPS to reduce the amount of data that needs to be replicated.
AnswerB

Replica lag occurs when the replica cannot keep up with the rate of changes from the primary. Increasing the replica's instance size gives it more resources to apply WAL data faster, reducing lag. This directly addresses the performance bottleneck.

Why this answer

Upgrading the read replica instance class provides more CPU and memory, which directly increases the WAL replay rate. In RDS for PostgreSQL, replica lag is primarily caused by the replica's inability to apply WAL changes as fast as the primary generates them. A larger instance class alleviates this bottleneck without incurring the cost of upgrading the primary instance.

Exam trap

The trap here is that candidates often confuse replica lag with primary performance, leading them to upgrade the primary (Option D) or add more replicas (Option C), when the real bottleneck is the replica's WAL replay capacity.

How to eliminate wrong answers

Option A is wrong because Multi-AZ is a high-availability feature that uses synchronous replication to a standby in a different AZ, not a solution for read replica lag; it does not improve asynchronous replication performance and adds cost without addressing the WAL replay bottleneck. Option C is wrong because adding more read replicas distributes the read load but does not reduce the lag on each individual replica; each replica still must apply the same volume of WAL changes from the primary, so lag per replica remains unchanged. Option D is wrong because upgrading the primary instance class with increased IOPS reduces the primary's write latency but does not affect the replica's ability to replay WAL; the primary already generates WAL at the same rate, and the bottleneck is on the replica side.

Practice this question →
7
MCQhard

A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application is deployed in a single AWS region. The company wants to improve performance for users in other regions and reduce the load on the origin servers. The SysOps administrator decides to use Amazon CloudFront. After implementing CloudFront, the administrator notices that the cache hit ratio is very low (around 10%) for the dynamic API responses that are served by the application. These API responses are personalized per user and change frequently. The administrator wants to improve performance for these dynamic requests while still using CloudFront. The application uses cookies for session management and the API responses depend on the user's session. The administrator must ensure that users receive the correct personalized content. Which configuration should the administrator use?

A.Use Lambda@Edge to generate personalized responses at the edge without forwarding all requests to the origin.
B.Configure CloudFront to use origin shield and enable keep-alive connections to the origin.
C.Configure CloudFront to forward cookies to the origin and enable caching based on cookies.
D.Disable caching for the API behavior in CloudFront and enable real-time logs.
AnswerA

Use Lambda@Edge to generate personalized responses at the edge. This allows dynamic content to be served from the edge without requiring a round trip to the origin, improving performance while maintaining correctness. It directly addresses the low cache hit ratio by avoiding caching altogether for personalized content.

Why this answer

For dynamic, personalized API responses that depend on user session cookies, caching is ineffective because each user's response is unique. Lambda@Edge allows you to run code at CloudFront edge locations to generate personalized responses or modify requests/responses. By using a Lambda function that inspects the session cookie and generates the appropriate API response at the edge, you can serve personalized content without forwarding every request to the origin.

This improves performance by reducing round trips and origin load while ensuring users receive correct personalized content. Options B, C, and D do not effectively address the need for dynamic personalization with low cache hit ratio.

Practice this question →
8
MCQmedium

An administrator runs the above command to list EC2 instances. The company wants to optimize costs. Which instance should the administrator consider terminating first?

A.i-0efgh5678 (t3.large, running in us-east-1b)
B.i-0abcd1234 (t3.medium, running in us-east-1a)
C.i-0mnop3456 (t3.medium, stopped in us-east-1c)
D.i-0ijkl9012 (t3.xlarge, running in us-east-1a)
AnswerC

Stopped instances still incur costs for attached resources.

Why this answer

The instance i-0mnop3456 is stopped but still incurs costs for EBS volumes and possibly Elastic IPs. Terminating it will eliminate those costs. The running instances are in use and may be necessary.

The t3.medium instances are smaller and may be needed.

Practice this question →
9
MCQeasy

A company wants to receive alerts when its AWS costs exceed a certain threshold. Which AWS service should be used?

A.Amazon CloudWatch
B.AWS Cost Explorer
C.AWS Trusted Advisor
D.AWS Budgets
AnswerD

Allows setting cost budgets and sending alerts.

Why this answer

AWS Budgets allows you to set custom cost and usage budgets and receive alerts when actual or forecasted costs exceed a defined threshold. It directly supports cost-based alerting with actions such as sending an SNS notification or applying an IAM policy to restrict resources when the budget limit is breached.

Exam trap

The trap here is that candidates confuse AWS Budgets with AWS Cost Explorer, assuming Cost Explorer can send alerts, when in fact Cost Explorer is only a reporting and analysis tool without native alerting capabilities.

How to eliminate wrong answers

Option A is wrong because Amazon CloudWatch monitors AWS resource utilization and application performance metrics, not cost thresholds; while it can trigger alarms on billing metrics if you enable detailed billing metrics, it is not the primary service for cost-based budget alerts. Option B is wrong because AWS Cost Explorer provides visualization and analysis of historical cost data but does not support proactive threshold-based alerts. Option C is wrong because AWS Trusted Advisor offers cost optimization recommendations and checks for idle resources, but it does not allow you to set custom cost thresholds or send alerts when costs exceed a specific amount.

Practice this question →
10
MCQmedium

A company runs a batch processing job every night that takes 2 hours on a single m5.xlarge EC2 instance. The job is fault-tolerant and can be interrupted. The SysOps administrator wants to reduce costs. Which solution is MOST cost-effective?

A.Use an On-Demand instance and set up a CloudWatch alarm to stop it when the job completes.
B.Use a Spot Instance with a Spot Fleet that includes a fallback to On-Demand if Spot is not available.
C.Use a Dedicated Host to run the job.
D.Purchase a Reserved Instance for the m5.xlarge instance.
AnswerB

A Spot Fleet is the correct choice here because it lets you request Spot Instances at a significantly lower cost while maintaining reliability with an On-Demand fallback. The nightly batch job is fault-tolerant, meaning it can restart or rerun if Spot capacity is reclaimed. If Spot capacity is unavailable or gets interrupted, the Spot Fleet automatically launches an On-Demand instance to ensure the job still completes, giving you a balance of cost savings and capacity assurance.

Why this answer

The most cost-effective solution is to use a Spot Instance with a Spot Fleet that includes a fallback to On-Demand if Spot is not available (Option B). The job is fault-tolerant and can be interrupted, making it ideal for Spot Instances which offer significant cost savings (up to 90% compared to On-Demand). The Spot Fleet with an On-Demand fallback ensures the job completes even if Spot capacity is unavailable.

Option A (On-Demand with CloudWatch alarm) does not reduce costs since On-Demand is more expensive. Option C (Dedicated Host) is costly and unnecessary for a batch job. Option D (Reserved Instance) requires a 1- or 3-year commitment and is not cost-effective for a 2-hour daily job.

Practice this question →
11
MCQeasy

A company stores large volumes of log data in Amazon S3. The logs are accessed frequently for the first 30 days, then occasionally for the next 60 days, and after 90 days they are rarely accessed but must be retained for 7 years for compliance. The SysOps administrator wants to minimize storage costs while ensuring data is available when needed. Which S3 lifecycle policy configuration should be applied?

A.Transition objects to S3 Standard-IA after 30 days, and to S3 Glacier after 60 days. Delete after 7 years.
B.Transition objects to S3 Glacier Deep Archive after 30 days, and delete after 7 years.
C.Transition objects to S3 One Zone-IA after 30 days, and to S3 Glacier Deep Archive after 90 days. Delete after 7 years.
D.Transition objects to S3 Standard-IA after 30 days, and to S3 Glacier Deep Archive after 90 days. Delete after 7 years.
AnswerD

This lifecycle policy matches the access patterns: frequent access -> Standard-IA after 30 days, occasional access for next 60 days (still in IA), then rarely accessed -> Deep Archive after 90 days. Deep Archive is the lowest-cost storage option for long-term retention. Deleting after 7 years meets compliance. This is the most cost-effective configuration.

Why this answer

It aligns the lifecycle transitions with the access patterns: frequent access for the first 30 days (S3 Standard), occasional access for the next 60 days (S3 Standard-IA), and rare access after 90 days (S3 Glacier Deep Archive, the lowest-cost storage class for long-term retention). The deletion after 7 years meets compliance requirements while minimizing costs by using progressively cheaper storage classes.

Exam trap

The trap here is that candidates may choose Option A because they think S3 Glacier is the standard archival tier, but they overlook that S3 Glacier Deep Archive is cheaper for 7-year retention and that the occasional-access period (days 31–90) is better served by S3 Standard-IA, not S3 Glacier.

How to eliminate wrong answers

Option A is wrong because transitioning to S3 Glacier after 60 days (instead of 90) would incur unnecessary retrieval costs and slower access during the occasional-access period (days 31–90), and S3 Glacier is more expensive than S3 Glacier Deep Archive for long-term retention. Option B is wrong because moving directly to S3 Glacier Deep Archive after 30 days ignores the frequent-access period, causing high retrieval costs and latency for logs that are still accessed often. Option C is wrong because S3 One Zone-IA is not resilient to AZ failures and is unsuitable for compliance data that must be retained for 7 years; also, transitioning after 30 days to One Zone-IA does not match the occasional-access pattern (days 31–90) as well as Standard-IA.

Practice this question →
12
MCQhard

A company runs a production Amazon DynamoDB table with provisioned capacity of 1000 write capacity units (WCU). The table experiences unpredictable spikes up to 2000 WCU, causing throttling. The SysOps administrator wants to minimize cost while handling the spikes. Which solution should be used?

A.Switch to on-demand capacity mode.
B.Increase provisioned WCU to 2000 to cover the peak.
C.Enable DynamoDB Auto Scaling with minimum 1000, maximum 2000 WCU.
D.Use a DynamoDB Accelerator (DAX) cache.
AnswerA

Switch to on-demand capacity mode: On-demand mode instantly accommodates usage spikes without requiring capacity planning or pre-provisioning. You pay per request, so there is no charge for unused provisioned capacity, making it highly cost-effective for unpredictable write traffic. It eliminates throttling errors because DynamoDB automatically scales write and read capacity to match your application's actual demand, even during sudden bursts.

Why this answer

Switching to on-demand capacity mode eliminates throttling during unpredictable spikes by automatically scaling write capacity up to the required 2000 WCU without any manual intervention or pre-provisioning. This minimizes cost because you pay only for the actual reads and writes consumed, avoiding the fixed cost of over-provisioning for peak capacity that may be rarely used.

Exam trap

The trap here is that candidates often choose DynamoDB Auto Scaling (Option C) thinking it handles spikes instantly, but they overlook the inherent scaling delay and the fact that it still requires a maximum capacity setting that may not cover sudden bursts, leading to throttling.

How to eliminate wrong answers

Option B is wrong because increasing provisioned WCU to 2000 permanently incurs higher base costs even during low-traffic periods, which contradicts the goal of minimizing cost. Option C is wrong because DynamoDB Auto Scaling adjusts capacity based on utilization metrics, but it cannot react instantly to sudden spikes up to 2000 WCU, leading to throttling during the scaling delay. Option D is wrong because DynamoDB Accelerator (DAX) is an in-memory cache that improves read performance, not write capacity, and does not address write throttling caused by insufficient WCU.

Practice this question →
13
MCQhard

A SysOps team manages a fleet of EC2 instances used for batch processing. The workload runs daily, taking approximately 6 hours. The instances are launched via an Auto Scaling group using On-Demand instances from a custom AMI. The team has noticed that while the instances are running, the CPU utilization is moderate, but the memory usage is high. After the batch completes, the instances are terminated. The team wants to reduce costs without changing the architecture. Which solution would be MOST cost-effective?

A.Modify the Auto Scaling group to use a mixed instances policy with a percentage of Spot Instances and a fallback to On-Demand.
B.Use a Compute Savings Plan covering the entire compute usage across the account.
C.Change the instance type to a memory-optimized family to reduce the number of instances needed.
D.Purchase Reserved Instances for the expected daily usage to get a lower hourly rate.
AnswerA

Spot Instances are ideal for fault-tolerant workloads like batch processing, offering large discounts.

Why this answer

Spot Instances can provide significant discounts (up to 90%) for fault-tolerant batch workloads, and the team can use a mixed instances policy with On-Demand as a fallback. Option B (memory optimized instances) would likely increase cost. Option C (reserved instances) is not suitable for short-lived, sporadic workloads.

Option D (savings plan) could help but still requires committing to a consistent amount, which may not align with the varying batch size. Option A offers the most flexibility and cost savings.

Practice this question →
14
MCQhard

A SysOps administrator is investigating a cost increase in a production AWS account. They notice that an EC2 instance with a Reservation has been running continuously for months. The instance type is m5.large in us-east-1. The administrator sees that the instance is using a Standard Reserved Instance (RI) that was purchased 6 months ago for a 1-year term. However, the current utilization shows that the instance is only used for 4 hours per day. What should the administrator do to optimize costs without affecting availability?

A.Stop the instance during off-hours using Instance Scheduler, but keep the RI as-is.
B.Sell the current RI on the Reserved Instance Marketplace and purchase a new Convertible RI for a smaller instance type.
C.Modify the existing RI to a smaller instance size (e.g., m5.large to m5.xlarge? no, smaller: e.g., t3.medium) and use Auto Scaling with a schedule to start/stop the instance during business hours.
D.Convert the RI to a Convertible RI and exchange it for a larger instance family to get more compute per hour.
AnswerC

Modifying RI to a smaller size matches usage; scheduled stop reduces running hours.

Why this answer

By modifying the existing Standard RI to a smaller instance size (e.g., within the same family or by converting to a Convertible RI to allow family changes), the administrator can better match the actual low utilization pattern. Additionally, using Auto Scaling with a scheduled scaling policy to start and stop the instance during business hours ensures availability during needed times and reduces waste. Option A is incorrect because stopping the instance does not stop the RI charges; Reserved Instance benefits are applied only to running instances, so the RI would be wasted during off-hours.

Option B is incorrect because selling the RI on the Reserved Instance Marketplace typically incurs a loss of the upfront payment and does not directly address the over-provisioning issue. Option D is incorrect because converting to a larger instance family would increase compute capacity per hour, leading to higher costs and even more waste given the low utilization.

Practice this question →
15
MCQmedium

A SysOps administrator manages a fleet of Amazon EC2 instances. The administrator needs to identify underutilized instances and receive recommendations for instance type changes to reduce costs. Which AWS service should be used to provide these rightsizing recommendations?

A.AWS Cost Explorer
B.AWS Trusted Advisor
C.AWS Compute Optimizer
D.Amazon CloudWatch Dashboard
AnswerC

AWS Compute Optimizer uses machine learning to analyze historical utilization metrics — including CPU, memory, EBS volume I/O, and network throughput — over a 14-day period and delivers specific recommendations for right-sizing EC2 instances, Auto Scaling groups, and EBS volumes. It provides a projected monthly cost savings estimate and a performance risk score for each recommendation, helping you balance cost and performance. You can also enable enhanced infrastructure metrics for even more precise suggestions, making it the appropriate tool for rightsizing EC2 instances.

Why this answer

AWS Compute Optimizer is the correct service because it uses machine learning to analyze historical utilization metrics (CPU, memory, network, and storage) of EC2 instances and generates rightsizing recommendations, including instance type changes, to reduce costs and improve performance. It directly addresses the need to identify underutilized instances and provide actionable recommendations for cost optimization.

Exam trap

The trap here is that candidates often confuse AWS Compute Optimizer with AWS Trusted Advisor, because both offer cost optimization checks, but Compute Optimizer is the only service that provides detailed, ML-driven rightsizing recommendations for EC2 instance types based on historical utilization data.

How to eliminate wrong answers

Option A is wrong because AWS Cost Explorer provides cost and usage data visualization and forecasting, but it does not analyze instance utilization metrics or generate specific rightsizing recommendations for EC2 instance types. Option B is wrong because AWS Trusted Advisor offers general best-practice checks, including cost optimization, but its EC2-specific recommendations are limited to idle instances and reserved instance utilization, not detailed rightsizing recommendations based on historical utilization patterns. Option D is wrong because Amazon CloudWatch Dashboard is a monitoring and visualization tool for metrics and logs, but it does not automatically analyze utilization data to produce instance type change recommendations; it requires manual setup and interpretation.

Practice this question →
16
MCQmedium

A company has an S3 bucket policy as shown. A developer tries to upload an object using the AWS CLI without the --no-verify-ssl flag. What will happen?

A.The upload will succeed only if the developer uses HTTP.
B.The upload will fail because the policy denies all s3:* actions.
C.The upload will fail because the policy requires explicit HTTPS.
D.The upload will succeed because the CLI uses HTTPS by default.
AnswerD

The bucket policy allows s3:PutObject only when the request is made over a secure transport, as captured by the aws:SecureTransport condition key. The AWS CLI uses the HTTPS endpoint by default, so the request's SecureTransport value is true and the Allow branch applies. Consequently the upload is authorized and completes successfully.

Why this answer

The bucket policy denies requests that do not use secure transport (HTTP) but allows HTTPS requests. The AWS CLI uses HTTPS by default, and since the developer did not use --no-verify-ssl, the request is made over HTTPS. Therefore, the upload succeeds.

Option D is correct. Option A is incorrect because the CLI uses HTTPS, not HTTP. Option B is incorrect because the policy does not deny all s3:* actions; it only denies requests over HTTP.

Option C is incorrect because the policy requires HTTPS, and the CLI complies, so the upload does not fail.

Practice this question →
17
MCQmedium

A company runs an e-commerce application on Amazon EC2 instances behind an Auto Scaling group. The application has a predictable baseline load from 8 AM to 8 PM daily and low load overnight. The SysOps administrator wants to optimize costs while ensuring sufficient capacity for the baseline load. Which purchasing option and scaling strategy should the administrator use?

A.Use On-Demand instances for the baseline and Spot Instances for any additional capacity.
B.Use Reserved Instances for the predicted baseline and On-Demand for any unexpected spikes.
C.Use Dedicated Hosts for all instances to maximize cost savings.
D.Use Spot Instances for all instances to minimize costs.
AnswerB

Reserved Instances should back the predictable baseline because they offer a substantial discount (up to 72% compared to On-Demand) for a commitment you know you will use, while On-Demand covers unexpected spikes without requiring a long-term contract. This combination minimizes cost on the steady-state load while retaining the flexibility to launch extra capacity at any moment, and it avoids the interruption risk of Spot for the mission-critical spikes.

Why this answer

Reserved Instances provide a significant discount (up to 72%) over On-Demand for predictable, steady-state workloads like the 8 AM to 8 PM baseline. On-Demand instances then cover any unexpected spikes without requiring upfront commitment, ensuring cost optimization while maintaining capacity for the predictable load.

Exam trap

The trap here is that candidates assume Spot Instances are always the cheapest option, but they fail to recognize that the predictable baseline load requires guaranteed availability, which Spot Instances cannot provide due to potential interruptions.

How to eliminate wrong answers

Option A is wrong because Spot Instances can be interrupted with a 2-minute warning when AWS needs capacity back, making them unsuitable for a baseline load that must be reliably available during business hours. Option C is wrong because Dedicated Hosts are a physical server dedicated to your use, which is far more expensive than Reserved Instances and provides no cost optimization benefit for a standard e-commerce application that does not require license compliance or physical isolation. Option D is wrong because Spot Instances are not suitable for all instances due to their potential for interruption, which would cause the application to fail during the predictable baseline load.

Practice this question →
18
MCQhard

A SysOps administrator notices that an S3 bucket's storage costs have increased significantly. The bucket stores log files and is configured with S3 Standard storage class. Most logs are accessed only once after 30 days. Which action will reduce costs without affecting data retrieval?

A.Create a lifecycle policy to transition objects to S3 Standard-IA after 30 days.
B.Create a lifecycle policy to transition objects to S3 Glacier Deep Archive after 30 days.
C.Create a lifecycle policy to transition objects to S3 Glacier Instant Retrieval after 30 days.
D.Create a lifecycle policy to transition objects to S3 One Zone-IA after 30 days.
AnswerC

S3 Glacier Instant Retrieval reduces storage cost while maintaining millisecond access.

Why this answer

Transitioning to S3 Glacier Instant Retrieval after 30 days reduces storage cost while maintaining millisecond access. Option A is wrong because S3 Standard-IA has retrieval fees that might increase cost for single access. Option B is wrong because S3 Glacier Deep Archive has long retrieval times (hours), making it unsuitable for logs that may need to be accessed occasionally.

Option D is wrong because S3 One Zone-IA is less durable (does not replicate across AZs) and may not be appropriate for log data.

Practice this question →
19
MCQmedium

A SysOps administrator is troubleshooting slow application performance. The application runs on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer. Amazon CloudWatch metrics show that the average CPU utilization across the instances is below 20%, but the application is still slow. What is the MOST likely cause of the performance issue?

A.The Auto Scaling group is scaling too aggressively, causing thrashing.
B.The Application Load Balancer has a sticky session configuration that is not distributing traffic evenly.
C.The application database is under-provisioned and is causing slow query responses.
D.The EC2 instances are using burstable performance and have exhausted their CPU credits.
AnswerC

An under-provisioned database can directly cause slow application responses while keeping EC2 CPU low because the application nodes spend most of their time blocked on database queries. Inadequate IOPS, insufficient memory for the buffer cache, or a suboptimal schema can lead to high query latency and connection queueing, which is not reflected in the web-tier CloudWatch CPU metric. The low average CPU is a classic sign of an external dependency bottleneck, making the database the most plausible root cause for the degraded user experience.

Why this answer

The most likely cause is that the application database is under-provisioned, leading to slow query responses. Even though EC2 CPU utilization is low, the application performance is bottlenecked by database latency. This is a common scenario where the database tier is the constraint, not the compute tier.

Exam trap

Candidates may assume low CPU means the compute layer is fine, but the real bottleneck could be the database tier. Don't automatically rule out downstream components.

Practice this question →
20
MCQmedium

A media company stores millions of video files in S3. Some files are accessed heavily after upload (when new) and rarely afterward; others are accessed unpredictably across months. The team cannot predict which files will be accessed and when. They want to minimize storage costs without risking retrieval latency penalties or per-object retrieval fees. Which storage class is appropriate?

A.Use S3 Intelligent-Tiering so objects automatically move between Frequent and Infrequent Access tiers based on access patterns, with no retrieval fees
B.Use S3 Standard-IA and configure a lifecycle policy to move objects back to Standard after every access
C.Use S3 Glacier Instant Retrieval for all objects because it offers the lowest storage cost with millisecond retrieval
D.Use S3 Standard for all objects because it has no retrieval fees and provides the best availability
AnswerA

Intelligent-Tiering handles the unpredictable access pattern automatically. Objects accessed within 30 days stay in Frequent Access. Unaccessed objects move to Infrequent Access (40 percent lower cost). No retrieval fee ensures there is no cost penalty when an old file is accessed unexpectedly. The per-object monitoring fee is offset by storage savings for objects over 128 KB.

Why this answer

S3 Intelligent-Tiering is the correct choice because it automatically moves objects between Frequent Access and Infrequent Access tiers based on changing access patterns, with no retrieval fees and no performance impact (millisecond latency). This matches the unpredictable access pattern described, as the service monitors access at the object level and adjusts storage tier without manual lifecycle rules or retrieval costs.

Exam trap

The trap here is that candidates often confuse S3 Intelligent-Tiering with S3 Standard-IA, assuming both have retrieval fees, or they incorrectly believe Glacier Instant Retrieval is always cheaper despite its retrieval fees and minimum storage duration penalties.

How to eliminate wrong answers

Option B is wrong because S3 Standard-IA charges a per-object retrieval fee (per GB retrieved) and a minimum storage duration fee (30 days), and moving objects back to Standard after every access would incur repeated retrieval fees and lifecycle transition costs, defeating cost minimization. Option C is wrong because S3 Glacier Instant Retrieval has a higher storage cost than Intelligent-Tiering for frequently accessed data and still incurs retrieval fees (per GB) for every access, plus a minimum 90-day storage charge, making it unsuitable for unpredictable access patterns. Option D is wrong because S3 Standard has the highest storage cost among the options, and while it has no retrieval fees, it does not optimize costs for files that become rarely accessed over time, leading to unnecessary expense.

Practice this question →
21
MCQhard

A company uses Amazon S3 to serve large files to users. The files are accessed frequently for the first 30 days after upload, then access drops significantly. The SysOps administrator wants to minimize storage costs while ensuring low-latency access for frequently accessed files and automatic optimization for changing access patterns. Which S3 storage class configuration should be used?

A.Use S3 Standard for 30 days, then transition to S3 Glacier Deep Archive.
B.Use S3 Intelligent-Tiering.
C.Use S3 Standard then transition to S3 Glacier Flexible Retrieval after 30 days.
D.Use S3 One Zone-IA for the first 30 days, then transition to S3 Standard-IA.
AnswerB

S3 Intelligent-Tiering is the correct choice because it automatically monitors access patterns at the object level and moves data between Frequent Access, Infrequent Access, and Archive Instant Access tiers without any retrieval fees or user action. This provides low-latency access for actively requested large files while silently reducing storage cost for objects that become cold. It is ideal for unknown, unpredictable, or changing access patterns because there is no static lifecycle rule to misjudge when data will be accessed again. A small monthly monitoring and automation fee per object applies, but it is typically negligible compared to the savings and avoids the risk of archive-tier retrieval delays.

Why this answer

S3 Intelligent-Tiering is the correct choice because it automatically moves objects between three access tiers (frequent, infrequent, and archive instant) based on changing access patterns, without any lifecycle rules or performance impact. This meets the requirement for low-latency access for frequently accessed files and automatic optimization, while minimizing storage costs as access drops after 30 days.

Exam trap

The trap here is that candidates often choose a lifecycle-based solution (like S3 Standard to Glacier) thinking it is automatic, but they overlook that lifecycle rules are static and do not adapt to changing access patterns, whereas S3 Intelligent-Tiering dynamically optimizes without manual intervention.

How to eliminate wrong answers

Option A is wrong because S3 Glacier Deep Archive has a retrieval time of 12-48 hours, which does not provide low-latency access for frequently accessed files, and it requires manual lifecycle rules rather than automatic optimization. Option C is wrong because S3 Glacier Flexible Retrieval has retrieval times of minutes to hours (typically 1-5 minutes for expedited, but with additional cost), which does not guarantee low-latency access, and it requires a lifecycle policy rather than automatic pattern adaptation. Option D is wrong because S3 One Zone-IA does not provide the durability of multiple Availability Zones and is not suitable for frequently accessed files due to retrieval costs, and transitioning to S3 Standard-IA after 30 days still requires manual lifecycle rules and does not automatically optimize for changing access patterns.

Practice this question →
22
MCQmedium

The finance team was surprised by a $12,000 spike in EC2 costs last month caused by a runaway Auto Scaling group. They want to receive an email alert within hours whenever any AWS service cost behaves unexpectedly, without manually setting fixed dollar thresholds for each service. Which AWS cost management feature provides this?

A.Enable Cost Anomaly Detection with an AWS services monitor and create an alert subscription to email the finance team when an anomaly is detected
B.Create an AWS Budget with a monthly EC2 cost threshold of $10,000 and an alert at 80 percent of the threshold
C.Enable AWS Cost Explorer and review the daily cost breakdown each morning to spot unexpected charges
D.Configure CloudWatch Billing alarms with a static threshold for each AWS service individually
AnswerA

Cost Anomaly Detection's ML model learns the historical spending pattern for each service. When EC2 (or any service) starts spending at an anomalous rate, the model detects it within hours. The alert subscription can notify via email or SNS with the anomaly amount, affected service, and percentage deviation. No manual threshold tuning is needed — the model self-calibrates.

Why this answer

Cost Anomaly Detection uses machine learning to model historical spending patterns for each AWS service and automatically detects unusual spikes without requiring manual thresholds. By creating an AWS services monitor and linking an alert subscription, the finance team receives email notifications within hours when any service deviates from its expected cost behavior, directly addressing the need for service-agnostic, threshold-free alerts.

Exam trap

The trap here is that candidates often confuse AWS Budgets or CloudWatch Billing alarms with anomaly detection, but those tools require manual static thresholds and do not automatically adapt to changing spending patterns across multiple services.

How to eliminate wrong answers

Option B is wrong because an AWS Budget with a fixed monthly EC2 cost threshold of $10,000 and an 80% alert requires manual threshold setting and only monitors EC2, not all services, and cannot detect unexpected behavior that stays under the threshold. Option C is wrong because manually reviewing AWS Cost Explorer daily is not an automated alerting mechanism and does not provide timely notification within hours of a spike. Option D is wrong because CloudWatch Billing alarms require configuring a static dollar threshold for each individual service, which is exactly what the finance team wants to avoid, and they do not adapt to changing spending patterns.

Practice this question →
23
MCQhard

A company uses Amazon S3 for static website hosting. The website serves thousands of users globally, and the company wants to reduce latency and lower data transfer costs. Which solution should the SysOps administrator implement?

A.Set up Amazon CloudFront as a content delivery network (CDN) in front of the S3 bucket.
B.Use S3 Intelligent-Tiering storage class.
C.Enable cross-region replication and serve from multiple buckets.
D.Enable S3 Transfer Acceleration on the bucket.
AnswerA

CloudFront caches content at edge locations, reducing latency and data transfer costs.

Why this answer

Amazon CloudFront is a global content delivery network (CDN) that caches static content at edge locations closer to users, reducing latency and lowering data transfer costs by minimizing direct requests to the S3 origin. By serving cached objects from edge locations, CloudFront also reduces the amount of data transferred from S3, which can significantly decrease S3 data transfer egress charges.

Exam trap

The trap here is that candidates confuse S3 Transfer Acceleration (which speeds up uploads) with a CDN solution for download performance, or they think cross-region replication alone solves latency without considering the need for a global caching layer.

How to eliminate wrong answers

Option B is wrong because S3 Intelligent-Tiering optimizes storage costs by moving objects between access tiers based on usage patterns, but it does not reduce latency or data transfer costs for global users. Option C is wrong because cross-region replication creates copies in multiple regions, but users still access a single bucket directly unless a routing mechanism like Route 53 latency-based routing is added, and it increases storage costs without providing edge caching benefits. Option D is wrong because S3 Transfer Acceleration uses AWS edge locations to speed up uploads to S3 over long distances, but it does not cache content for downloads or reduce latency for end users retrieving static website content.

Practice this question →
24
MCQeasy

A company runs a mix of Amazon EC2 instances and AWS Fargate tasks that are used for both production and development workloads. The usage is steady and predictable. The SysOps administrator wants to maximize cost savings across both compute services without having to manage specific instances or sizes. Which purchasing option should the administrator recommend?

A.Purchase Compute Savings Plans for a 1-year or 3-year term with a commitment that covers the expected compute spend.
B.Purchase EC2 Instance Savings Plans for the most commonly used instance family and region.
C.Purchase Standard Reserved Instances for the EC2 instances and convert Fargate tasks to use Spot Instances.
D.Use On-Demand instances for both EC2 and Fargate because the administrator does not want to make a commitment.
AnswerA

Compute Savings Plans are the right choice for a mixed EC2 and Fargate environment because the hourly commitment automatically applies to eligible compute usage across EC2 instances, Fargate tasks, and Lambda functions within the chosen region. Unlike EC2 Instance Savings Plans, they do not lock you to an instance family or size, so you can change instance types or refactor to containers without losing the discounted rate. A 1-year or 3-year term with a commitment that matches steady-state spend yields significant savings over On-Demand.

Why this answer

Compute Savings Plans offer the most flexibility, automatically applying to EC2 instances (regardless of instance family, size, or region) and Fargate tasks. Since the company has a mix of both services and wants to maximize savings without managing specific instances or sizes, a 1-year or 3-term Compute Savings Plan with a commitment matching expected spend provides up to 66% savings while covering all compute usage. This aligns with the steady and predictable workload described.

Exam trap

AWS often tests the distinction between Compute Savings Plans and EC2 Instance Savings Plans, where candidates mistakenly choose the latter thinking it covers all EC2 usage, but fail to recognize that Compute Savings Plans also include Fargate and Lambda, making them the only option for a mixed compute environment.

How to eliminate wrong answers

Option B is wrong because EC2 Instance Savings Plans are restricted to a specific instance family within a region, which does not cover Fargate tasks and would not provide the cross-service flexibility needed for the mixed workload. Option C is wrong because Standard Reserved Instances apply only to EC2 instances and require a specific instance family and size commitment, while converting Fargate tasks to Spot Instances introduces interruption risk and does not guarantee cost savings for steady workloads. Option D is wrong because On-Demand pricing offers no discount, and the administrator explicitly wants to maximize cost savings, which requires a commitment-based purchasing option.

Practice this question →
25
Multi-Selectmedium

A company wants to reduce costs for a production Amazon RDS for MySQL DB instance that is running 24/7 but only heavily used during business hours (9 AM to 5 PM). Which TWO actions would be MOST effective in optimizing costs without significantly impacting performance during peak hours?

Select 2 answers
A.Enable Multi-AZ deployment for high availability.
B.Purchase Reserved Instances for the DB instance.
C.Migrate from Provisioned IOPS (io1) storage to General Purpose (gp3) storage.
D.Use AWS Application Auto Scaling to schedule scale-down of the instance size outside business hours.
E.Enable Auto Scaling for the DB instance.
AnswersB, D

Reserved Instances provide a discount for consistent usage, reducing cost.

Why this answer

(Multi-AZ) increases cost and is not needed for cost optimization. Option B (reserved instances) provides a discount for consistent usage. Option C (Migrate to gp3 storage) can be more cost-effective than provisioned IOPS for many workloads, but it is not the most effective action because the instance is only heavily used during business hours.

Option D (scheduled scaling) can reduce instance size during off-peak hours, saving cost. Option E (Auto Scaling) is not applicable to standard RDS without additional services like Aurora Auto Scaling. Correct answers: B and D.

Practice this question →
26
Multi-Selecteasy

A SysOps administrator needs to reduce data transfer costs for a web application hosted on EC2 instances in a VPC. The application serves content to users over the internet. Which TWO actions will help reduce data transfer costs? (Choose TWO.)

Select 2 answers
A.Move all instances to private subnets and use AWS Direct Connect for user access.
B.Use a VPC Gateway Endpoint for Amazon S3 to keep S3 traffic within AWS.
C.Use Amazon CloudFront to cache and serve static content.
D.Use an Application Load Balancer to distribute traffic.
E.Use a larger NAT Gateway to improve throughput.
AnswersB, C

Gateway endpoints are free and reduce data transfer costs to S3.

Why this answer

The correct answers are B and C. Using a VPC Gateway Endpoint for Amazon S3 allows instances to access S3 over the AWS network without traversing the internet, reducing data transfer costs. Amazon CloudFront caches content at edge locations worldwide, so users receive content from edge locations instead of the EC2 origin, reducing data transfer from EC2 to the internet.

Option A is incorrect because migrating to private subnets and using AWS Direct Connect does not serve users over the internet; Direct Connect is a dedicated network connection that does not reduce data transfer costs for internet users. Option D is incorrect because an Application Load Balancer distributes traffic but does not inherently reduce data transfer costs; it may even add cost. Option E is incorrect because a larger NAT Gateway increases cost and does not reduce data transfer costs for outbound traffic.

Practice this question →
27
MCQhard

A company runs a web application on Amazon EC2 instances in an Auto Scaling group. The application uses Amazon EBS volumes (gp2) for data storage. The SysOps administrator notices that the storage costs are high, and the application's IOPS requirements are consistently below 3000. The administrator wants to reduce storage costs without affecting performance. Which action should the administrator take?

A.Modify the EBS volumes to use Provisioned IOPS (io1) volumes and set IOPS to 2000.
B.Convert the EBS volumes from gp2 to gp3 volume type.
C.Implement an Amazon EBS snapshot lifecycle policy to delete old snapshots and reduce storage costs.
D.Enable EBS optimization on the EC2 instances to improve throughput and reduce costs.
AnswerB

gp3 volumes provide a baseline of 3000 IOPS and 125 MB/s throughput for every volume, independent of size, and the per-GB price is roughly 20% lower than gp2. This makes gp3 both cheaper and more predictable for workloads under 3000 IOPS, as it does not rely on burst credits like gp2. Converting existing gp2 volumes to gp3 can be performed non-disruptively, and would reduce the running EBS cost while still exceeding the application's performance requirements.

Why this answer

Gp3 volumes offer a baseline performance of 3000 IOPS and 125 MB/s throughput at a lower cost than gp2 volumes, making them ideal for workloads with IOPS requirements consistently below 3000. By converting from gp2 to gp3, the administrator can reduce storage costs without any performance impact, as gp3 provides the same or better baseline performance at a lower price per GB.

Exam trap

The trap here is that candidates may confuse cost reduction strategies for EBS volumes with snapshot management or instance-level optimizations, failing to recognize that gp3 is the direct, cost-effective replacement for gp2 when IOPS requirements are below the gp3 baseline.

How to eliminate wrong answers

Option A is wrong because Provisioned IOPS (io1) volumes are designed for high-performance workloads requiring more than 16,000 IOPS and are significantly more expensive than gp2 or gp3, so using io1 with only 2000 IOPS would increase costs unnecessarily. Option C is wrong because deleting old snapshots reduces snapshot storage costs, not the cost of the EBS volumes themselves, and the question specifically asks about reducing storage costs for the EBS volumes used by the application. Option D is wrong because EBS optimization is a feature that provides dedicated network bandwidth for EBS traffic, improving throughput and reducing latency, but it does not directly reduce storage costs; it may even incur additional costs if the instance type requires it.

Practice this question →
28
MCQhard

A company runs a web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application reads data from an Amazon RDS for MySQL database. During peak hours, the database CPU utilization is consistently high, and the application experiences increased latency. The SysOps administrator observes that 90% of database queries are read-only. Which combination of actions will both improve performance and optimize costs?

A.Enable Multi-AZ for the RDS instance and scale up the instance size
B.Implement a read replica for the RDS instance and modify the application to route read queries to the read replica
C.Enable Amazon RDS Performance Insights and increase the storage allocation
D.Implement Amazon ElastiCache for Memcached in front of the database and migrate read-heavy queries to cache
AnswerB

Implementing a read replica creates a separate RDS instance that uses asynchronous replication to maintain a copy of the primary database, and it has its own endpoint that can handle read traffic. By modifying the application to route SELECT queries to the read replica (and keeping write operations on the primary), you offload CPU-intensive read workloads from the primary instance, directly alleviating high CPU utilization. This is a proven pattern for read-heavy applications because it scales read capacity independently and is more cost-effective than scaling up the primary, as you only size the primary for write throughput.

Why this answer

Implementing a read replica offloads read-heavy (90%) queries from the primary RDS instance, reducing CPU utilization and latency. Modifying the application to route read queries to the replica distributes the workload, improving performance while avoiding costly vertical scaling. This optimizes costs by using a smaller primary instance and paying only for the replica's resources.

Exam trap

The trap here is that candidates often confuse Multi-AZ (high availability) with read replicas (performance scaling), or assume caching (ElastiCache) is always the best choice for read-heavy workloads without considering the simplicity and cost-effectiveness of read replicas for database-level offloading.

How to eliminate wrong answers

Option A is wrong because enabling Multi-AZ provides high availability, not performance improvement, and scaling up the instance size increases costs without addressing the read-heavy workload. Option C is wrong because Performance Insights is a monitoring tool that does not reduce CPU utilization or latency, and increasing storage allocation does not improve query performance. Option D is wrong because ElastiCache for Memcached is a caching layer that can reduce database load, but it requires application code changes to cache read queries and does not directly offload read queries like a read replica; it is more suitable for caching specific data, not all read queries.

Practice this question →
29
MCQeasy

A company runs a batch processing application on Amazon EC2 that runs for 2 hours every night. The workload can tolerate interruptions. Which EC2 purchasing option provides the lowest cost for this use case?

A.On-Demand Instances
B.Reserved Instances
C.Spot Instances
D.Dedicated Hosts
AnswerC

Spot Instances operate using spare EC2 capacity that AWS makes available at a significantly reduced hourly rate—often up to 90% off On-Demand pricing. This is the best fit here because the nightly 2-hour batch is both short and fault-tolerant: if capacity is reclaimed, work can be re-queued or resumed without violating the batch window. You can further reduce interruption risk by using a Spot Fleet with multiple instance types and by implementing checkpointing so progress is saved between runs. The result is a dramatic cost reduction for a workload that would otherwise be idling and paying full price.

Why this answer

Spot Instances are the correct choice because the workload is fault-tolerant, runs for a fixed 2-hour window nightly, and can tolerate interruptions. Spot Instances offer significant cost savings (up to 90% off On-Demand) by using spare EC2 capacity, which aligns perfectly with a batch job that can be retried if interrupted.

Exam trap

The trap here is that candidates may choose Reserved Instances because they see a predictable nightly schedule, but they overlook that Reserved Instances are cost-effective only for 24/7 workloads, not for short, interruptible batch jobs where Spot Instances provide far greater savings.

How to eliminate wrong answers

Option A is wrong because On-Demand Instances provide no discount and are not cost-optimal for a predictable, interruptible workload. Option B is wrong because Reserved Instances require a 1- or 3-year commitment and are designed for steady-state, always-on workloads, not a short 2-hour nightly batch job. Option D is wrong because Dedicated Hosts are a physical server dedicated to a single customer, incurring high costs for licensing or compliance needs, and are overkill for a batch processing application that can tolerate interruptions.

Practice this question →
30
MCQmedium

A company runs a batch processing application on Amazon EC2 instances every night. The job takes exactly 1 hour to complete and is time-sensitive. The SysOps administrator wants to minimize compute costs while ensuring the job can be interrupted and resumed if needed. Which EC2 purchasing option is most cost-effective?

A.On-Demand Instances
B.Reserved Instances (Standard 1-year)
C.Spot Instances
D.Dedicated Hosts
AnswerC

Spot Instances let you bid for unused EC2 capacity at discounts of up to 90% compared to On-Demand pricing. AWS can reclaim that capacity with a two-minute interruption notice, but because this batch processing job is checkpointed and resumable, an interruption simply means restarting from the last saved state and continuing toward completion. This makes Spot the most cost-effective option for this workload, especially since the job is inherently fault-tolerant and runs only for short periods.

Why this answer

Spot Instances are the most cost-effective option because the batch job is fault-tolerant (can be interrupted and resumed) and runs for exactly 1 hour nightly. Spot Instances offer up to 90% discount compared to On-Demand, and with the ability to handle interruptions via checkpointing, they meet the requirement for cost minimization while supporting resumption.

Exam trap

The trap here is that candidates often assume Spot Instances are unsuitable for time-sensitive jobs due to potential interruptions, but the question explicitly states the job can be interrupted and resumed, making Spot the correct cost-effective choice over Reserved Instances or On-Demand.

How to eliminate wrong answers

Option A is wrong because On-Demand Instances provide no discount and are the most expensive option for a predictable nightly workload, failing to minimize costs. Option B is wrong because Reserved Instances require a 1-year commitment and are not cost-effective for a job that runs only 1 hour per night, as the upfront cost would not be amortized efficiently. Option D is wrong because Dedicated Hosts are designed for licensing or compliance requirements, not for cost savings, and are significantly more expensive than other options for this use case.

Practice this question →
31
MCQhard

A company is using Amazon S3 to store historical data. The data is accessed frequently for the first 30 days, then accessed infrequently for the next 90 days, and after 120 days it is rarely accessed but must be retained for 7 years for compliance. Which S3 lifecycle policy provides the LOWEST cost while meeting these requirements?

A.Standard for 30 days, then transition to Standard-IA for 90 days, then to Glacier Deep Archive.
B.Standard for 30 days, then transition to One Zone-IA for 90 days, then to Glacier Deep Archive.
C.Standard for 120 days, then transition to Glacier Deep Archive.
D.Standard for 30 days, then transition to Glacier for the remaining life.
AnswerA

Optimizes cost by using appropriate storage classes for each access pattern.

Why this answer

It aligns the storage class transitions precisely with the access patterns: Standard for frequent access (first 30 days), Standard-IA for infrequent access (next 90 days), and Glacier Deep Archive for long-term retention (after 120 days). This minimizes cost by avoiding paying for premium storage when data is rarely accessed, while still meeting the 7-year compliance requirement at the lowest possible storage cost.

Exam trap

The trap here is that candidates often overlook the compliance durability requirement and choose One Zone-IA for cost savings, or they fail to optimize the infrequent access period and keep data in Standard too long, both of which increase cost or risk data loss.

How to eliminate wrong answers

Option B is wrong because One Zone-IA is not designed for data that must be retained for compliance; it offers no resilience against the loss of a single Availability Zone, which violates the durability requirement for long-term retention. Option C is wrong because keeping data in Standard for 120 days incurs higher costs than transitioning to Standard-IA after 30 days, as the data is infrequently accessed during days 31–120, making it a more expensive choice. Option D is wrong because transitioning directly to Glacier (now S3 Glacier Flexible Retrieval) after 30 days ignores the infrequent access period (days 31–120) where Standard-IA would be cheaper than Glacier, and Glacier Deep Archive is the lowest-cost option for the rarely accessed 7-year retention period.

Practice this question →
32
MCQhard

A company stores application log files in an Amazon S3 bucket. The logs are accessed frequently for the first 30 days, then rarely accessed but must be retrievable within 12 hours. After 1 year, the logs must be archived for compliance with a retention period of 5 years, during which retrievals are expected to be extremely rare (one or two per year) and retrieval time of 12 hours is acceptable. The SysOps administrator wants to minimize storage costs. Which S3 lifecycle policy configuration should be used?

A.After 30 days, transition to S3 Standard-IA; after 365 days, transition to S3 Glacier Deep Archive; delete after 5 years.
B.After 30 days, transition to S3 Glacier Flexible Retrieval; after 365 days, transition to S3 Glacier Deep Archive; delete after 5 years.
C.After 30 days, transition to S3 Glacier Flexible Retrieval; delete after 5 years.
D.After 30 days, transition to S3 Glacier Deep Archive; delete after 5 years.
AnswerB

This lifecycle provides cost-optimized storage: S3 Standard for the first 30 days (frequent access), S3 Glacier Flexible Retrieval for the next 335 days (rare access, 12-hour retrieval acceptable), and S3 Glacier Deep Archive for the final 4+ years (extremely rare access, lowest cost). This minimizes overall costs while meeting retrieval requirements.

Why this answer

It uses S3 Glacier Flexible Retrieval for the first year after the initial 30 days, which meets the 12-hour retrieval requirement at lower cost than S3 Standard-IA, then transitions to S3 Glacier Deep Archive for the remaining 4 years to minimize storage costs for extremely rare retrievals. The lifecycle policy transitions objects after 30 days to S3 Glacier Flexible Retrieval (retrieval time minutes to 12 hours), then after 365 days to S3 Glacier Deep Archive (retrieval time 12 hours), and deletes after 5 years, aligning with the access patterns and compliance retention.

Exam trap

The trap here is that candidates often choose S3 Standard-IA (Option A) because it seems logical for infrequent access, failing to recognize that S3 Glacier Flexible Retrieval provides lower storage costs for data that is rarely accessed but still needs retrieval within 12 hours, and that a multi-tier lifecycle (Option B) is more cost-effective than a single transition.

How to eliminate wrong answers

Option A is wrong because transitioning to S3 Standard-IA after 30 days is not cost-optimal for data that is rarely accessed after the first 30 days; S3 Glacier Flexible Retrieval offers lower storage costs for infrequent access with a 12-hour retrieval window. Option C is wrong because it does not transition to S3 Glacier Deep Archive after 1 year, missing the opportunity to further reduce storage costs for the 4-year archival period where retrievals are extremely rare. Option D is wrong because transitioning directly to S3 Glacier Deep Archive after 30 days is premature and more expensive than using S3 Glacier Flexible Retrieval for the first year, as Deep Archive has higher retrieval costs and is designed for long-term archival, not for data that may still be accessed occasionally within 12 hours.

Practice this question →
33
MCQmedium

A company runs a production web application on a single Amazon EC2 instance. The application experiences a predictable and steady workload 24/7. The SysOps administrator wants to minimize compute costs for this instance while ensuring it remains available during the expected workload. Which EC2 purchasing option should the administrator use?

A.On-Demand Instances
B.Reserved Instances
C.Spot Instances
D.Dedicated Hosts
AnswerB

Reserved Instances offer a significant hourly discount in exchange for a one- or three-year commitment, and a Standard RI is best suited for steady-state, predictable production workloads like this always-on web app. By paying all or part of the cost upfront, you can reduce the effective hourly price by up to 72% compared to On-Demand. Because the workload is constant, the utilization will easily justify the commitment, making this the optimal cost-optimization strategy.

Why this answer

Reserved Instances (RIs) are the most cost-effective option for a predictable, steady-state workload running 24/7. By committing to a 1- or 3-year term, you receive a significant discount (up to 72%) compared to On-Demand pricing, while still ensuring the instance remains available for the expected workload. This matches the requirement to minimize compute costs without sacrificing availability.

Exam trap

The trap here is that candidates often choose Spot Instances for cost savings, overlooking the critical requirement of 'remaining available during the expected workload' — Spot Instances can be interrupted at any time, making them unsuitable for production workloads that need consistent availability.

How to eliminate wrong answers

Option A (On-Demand Instances) is wrong because, while they provide full availability, they are the most expensive option for a steady 24/7 workload and do not minimize costs. Option C (Spot Instances) is wrong because they can be terminated by AWS with a 2-minute notification when capacity is reclaimed, making them unsuitable for a production web application that must remain available during the expected workload. Option D (Dedicated Hosts) is wrong because they are designed for regulatory or licensing requirements (e.g., per-socket or per-core licensing) and are significantly more expensive than Reserved Instances, offering no cost benefit for a standard single-instance workload.

Practice this question →

Ready to test yourself?

Try a timed practice session using only Soa Cost Performance questions.

Start 20-question session