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CCNA Soa Cost Performance Questions

49 of 199 questions · Page 3/3 · Soa Cost Performance topic · Answers revealed

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151
Multi-Selectmedium

An EC2 Auto Scaling group runs a stateless web application with predictable daily peaks. Which two actions can reduce cost while preserving capacity during peak periods? (Choose 2.)

Select 2 answers
A.Configure scheduled scaling actions for the known peak window.
B.Use a mixed instances policy with some Spot capacity where interruption is acceptable.
C.Run all instances as On-Demand at maximum peak size all day.
D.Disable health checks to avoid instance replacement.
AnswersA, B

Scheduled scaling adds capacity before predictable demand.

Why this answer

Option A is correct because scheduled scaling allows you to proactively increase capacity before the predictable daily peak and reduce it afterward, ensuring you only pay for the resources needed during the peak window. This avoids over-provisioning for the entire day, directly reducing costs while maintaining performance during high-demand periods.

Exam trap

The trap here is that candidates may think disabling health checks saves money by avoiding instance replacements, but this actually risks application availability and can increase costs due to undetected failures, while the real cost-saving mechanisms are proactive scaling and using cheaper instance types like Spot.

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152
MCQmedium

A company runs a critical application on an Amazon RDS for MySQL DB instance. The company needs to ensure high availability and automatic failover in the event of a failure. The company also wants to optimize costs. Which solution should the company implement?

A.Create a read replica in a different Availability Zone and manually promote it during failure.
B.Create a Multi-AZ deployment for the RDS instance.
C.Use Amazon RDS Proxy to manage connections and improve failover.
D.Use a larger DB instance class to improve performance and reliability.
AnswerB

Multi-AZ provides automatic failover and is cost-effective.

Why this answer

Multi-AZ deployment provides automatic failover to a standby instance in a different Availability Zone, ensuring high availability. It is cost-effective compared to a manual standby. A read replica does not provide automatic failover.

An RDS proxy improves connection pooling but not failover. Using a larger instance increases cost without adding redundancy.

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153
MCQeasy

A company uses S3 standard storage for all data. They have data that is accessed rarely but must be retained for 7 years. Which storage class would be MOST cost-effective?

A.S3 One Zone-IA
B.S3 Standard
C.S3 Glacier Deep Archive
D.S3 Intelligent-Tiering
AnswerC

Deep Archive is designed for long-term retention at low cost.

Why this answer

Option C is correct because S3 Glacier Deep Archive is the lowest-cost storage for long-term archival. S3 Standard is expensive, S3 IA is for infrequent access but not long-term, and S3 One Zone IA is less durable.

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154
MCQhard

A company runs a critical application on a fleet of EC2 instances that process real-time financial transactions. The application requires consistent low latency. The SysOps administrator notices that the application's latency increases periodically due to noisy neighbors. The administrator wants to optimize performance predictability. Which instance type should the administrator choose?

A.Burstable Performance Instances (T3)
B.Dedicated Instances
C.Spot Instances
D.Reserved Instances
AnswerB

Dedicated Instances provide physical isolation, eliminating noisy neighbors.

Why this answer

Option D is correct because Dedicated Instances run on hardware dedicated to a single customer, eliminating the noisy neighbor effect. Option A is wrong because Burstable Performance Instances (T2, T3) are designed for variable workloads and do not provide consistent performance. Option B is wrong because Spot Instances are not suitable for critical, latency-sensitive applications.

Option C is wrong because Reserved Instances provide a discount but do not isolate the instance from other customers.

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155
MCQmedium

A company has an Amazon DynamoDB table that stores historical data. The table is accessed infrequently but when queried requires consistent single-digit millisecond latency. The SysOps administrator wants to minimize storage costs while maintaining the required performance. Which DynamoDB table class should the administrator use?

A.DynamoDB Standard
B.DynamoDB Standard-IA (Infrequent Access)
C.DynamoDB On-Demand
D.DynamoDB Provisioned
AnswerB

Standard-IA reduces storage costs for infrequently accessed tables while maintaining single-digit millisecond latency, fitting the use case perfectly.

Why this answer

DynamoDB Standard-IA (Infrequent Access) is designed for tables that are accessed less than once per month, offering lower storage costs than DynamoDB Standard while maintaining the same single-digit millisecond latency for queries. Since the table stores historical data with infrequent access but requires consistent performance, Standard-IA minimizes storage costs without sacrificing latency.

Exam trap

The trap here is confusing DynamoDB table classes (Standard vs Standard-IA) with billing modes (On-Demand vs Provisioned), leading candidates to choose a billing mode instead of the correct table class for storage cost optimization.

How to eliminate wrong answers

Option A is wrong because DynamoDB Standard is optimized for frequently accessed data and has higher storage costs, making it suboptimal for infrequently accessed historical data. Option C is wrong because DynamoDB On-Demand is a billing mode (not a table class) that charges per request and is typically more expensive for unpredictable workloads, but it does not address storage cost optimization for infrequent access. Option D is wrong because DynamoDB Provisioned is also a billing mode (not a table class) that requires capacity planning and does not inherently reduce storage costs; it focuses on throughput rather than storage efficiency.

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156
Matchingmedium

Match each AWS security service to its purpose.

Drag a concept onto its matching description — or click a concept then click the description.

Concepts
Matches

Identity and access management

Key management and encryption

Rotate and manage secrets

Web application firewall

DDoS protection

Why these pairings

These are key AWS security services.

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157
MCQeasy

A company uses Amazon S3 to store large files that are frequently accessed for the first 30 days after upload. After 30 days, access frequency drops significantly but users still need retrieval within minutes. 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 the company use?

A.Use S3 Standard for all objects, and manually move older objects to S3 Standard-IA after 30 days.
B.Use S3 Intelligent-Tiering
C.Use S3 Standard-IA for all objects, and accept higher retrieval costs for the first 30 days.
D.Use S3 Glacier Instant Retrieval
AnswerB

S3 Intelligent-Tiering automatically optimizes costs by moving objects between frequent and infrequent access tiers based on usage. It provides low latency and no retrieval charges, making it ideal for data with fluctuating access patterns.

Why this answer

B is correct because S3 Intelligent-Tiering automatically moves objects between two access tiers (frequent and infrequent access) based on changing access patterns, with no retrieval fees and low-latency access. This matches the requirement of frequent access for the first 30 days, then infrequent access with minutes-later retrieval, while minimizing storage costs without manual intervention.

Exam trap

The trap here is that candidates often confuse S3 Intelligent-Tiering with S3 Standard-IA, assuming the latter is cheaper for infrequent access, but they overlook that S3 Standard-IA has retrieval fees and higher per-GB cost for frequent access, making Intelligent-Tiering the optimal choice for automatic cost optimization with changing patterns.

How to eliminate wrong answers

Option A is wrong because manually moving objects to S3 Standard-IA after 30 days introduces operational overhead and does not automatically adapt to changing access patterns, violating the requirement for automatic optimization. Option C is wrong because using S3 Standard-IA for all objects incurs higher per-GB storage costs for the first 30 days (compared to S3 Standard) and a per-object retrieval fee for every access, making it cost-inefficient for frequently accessed data. Option D is wrong because S3 Glacier Instant Retrieval is designed for long-term archival with retrieval in milliseconds, but its storage costs are higher than S3 Standard-IA for data accessed within 30 days, and it lacks automatic tiering to adapt to changing patterns.

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158
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 allow you to use spare EC2 capacity at up to 90% discount compared to On-Demand. The workload is interruption-tolerant and fits the nightly batch window well, making this the most cost-effective option.

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.

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159
MCQmedium

A company uses an Application Load Balancer (ALB) to distribute traffic to EC2 instances. The SysOps team wants to reduce costs by ensuring that idle capacity is minimized. Which configuration should they implement?

A.Configure an Auto Scaling group with a step scaling policy based on CPU utilization.
B.Configure an Auto Scaling group with a target tracking scaling policy based on ALB request count per target.
C.Increase the number of EC2 instances in the Auto Scaling group to handle peak load.
D.Set the Auto Scaling group desired capacity to the maximum expected load.
AnswerB

Target tracking adjusts capacity to maintain a target metric, reducing idle instances.

Why this answer

Option A is correct because a target tracking policy automatically adjusts capacity based on demand, minimizing idle resources. Option B is wrong because step scaling can be used but is less efficient than target tracking. Option C is wrong because adding more instances increases idle capacity.

Option D is wrong because fixed instance count does not adapt to demand.

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160
MCQeasy

A company wants to reduce data transfer costs for traffic between EC2 instances in the same AWS Region. Which action should the SysOps administrator take?

A.Use Elastic IP addresses for all instances
B.Place instances in public subnets and route traffic through a NAT Gateway
C.Ensure instances communicate using private IP addresses within the same VPC
D.Use VPC endpoints to communicate between instances
AnswerC

Private IP traffic within a VPC is free.

Why this answer

Option D is correct because using private IP addresses avoids data transfer charges over the internet. Public IPs incur costs. VPC endpoints are for accessing AWS services, not for instance-to-instance traffic.

NAT Gateway adds cost. Direct Connect is for on-premises connectivity and is expensive.

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161
MCQeasy

A company has three EC2 instances as shown in the exhibit. The company pays for a t3.micro Reserved Instance. Which instance(s) will receive the RI discount?

A.Only i-0abcd1234
B.i-0abcd1234 and i-0abcd5678
C.i-0abcd1234 and i-0abcd9012
D.All three instances
AnswerA

RI applies to running t3.micro instance.

Why this answer

Option A is correct because RI discounts apply to running instances of the same instance size (or size flexible family). The t3.micro RI covers t3.micro instances; the t3.medium is larger and not covered. The stopped instance does not run, so no discount.

Option B is wrong because the stopped instance does not run. Option C is wrong because t3.medium is not covered. Option D is wrong because only the t3.micro running instance qualifies.

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162
MCQhard

A company hosts a multi-tier web application on AWS. The application consists of an Application Load Balancer (ALB), a fleet of Amazon EC2 instances running in an Auto Scaling group, and an Amazon RDS for MySQL database. The application is accessed by users worldwide. Recently, the company has expanded to new geographic regions, and users in those regions are experiencing high latency. The SysOps administrator is tasked with optimizing performance for global users while keeping costs low. The administrator has already implemented Amazon CloudFront as a CDN for static content. However, dynamic content that requires database queries is still slow. The application's Auto Scaling group is configured with a dynamic scaling policy based on average CPU utilization, but the scaling is not responsive enough during traffic spikes, causing performance degradation. Additionally, the database is a single db.r5.large instance in the us-east-1 region, and all traffic must hit that database, causing high latency for remote users. The administrator needs to propose a comprehensive solution that addresses both compute and database performance issues globally, while considering cost. Which solution is MOST effective?

A.Increase the minimum and maximum size of the Auto Scaling group and use a step scaling policy based on memory utilization.
B.Use Amazon Aurora Global Database to create read replicas in other regions, and configure the Auto Scaling group with a target tracking scaling policy based on request count per target.
C.Implement Amazon ElastiCache for Redis to cache database queries, and use predictive scaling for the Auto Scaling group.
D.Use larger EC2 instances (e.g., c5.2xlarge) for the application tier and provision a Multi-AZ RDS instance for better performance.
AnswerB

Aurora Global Database provides low-latency reads globally, and request-based scaling is more responsive.

Why this answer

Option D is correct because using Aurora Global Database provides a low-latency global read replica for the dynamic content, and using a target tracking scaling policy based on request count per target is more responsive than CPU-based scaling for web applications. Option A is wrong because increasing instance sizes is expensive and does not address global latency. Option B is wrong because adding more instances in a single region does not reduce latency for global users.

Option C is wrong because using ElastiCache can reduce database load but does not reduce latency for write operations, and predictive scaling may not be accurate for unpredictable spikes.

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163
MCQeasy

A SysOps administrator notices that some Amazon S3 objects have not been accessed for over 90 days and need to be retained for compliance purposes. The administrator wants to reduce storage costs by moving these objects to the lowest-cost storage class. Which action should the administrator take?

A.Manually move the objects to S3 One Zone-IA.
B.Create an S3 lifecycle rule to transition objects older than 90 days to S3 Glacier Deep Archive.
C.Use S3 Intelligent-Tiering.
D.Enable S3 Versioning and create a lifecycle rule to delete old versions.
AnswerB

Correct. A lifecycle rule can automatically transition objects to Glacier Deep Archive after 90 days, reducing cost while retaining data for compliance.

Why this answer

Option B is correct because S3 Glacier Deep Archive is the lowest-cost storage class in Amazon S3, designed for long-term retention of data that is accessed infrequently. An S3 lifecycle rule can automatically transition objects older than 90 days to this class, reducing costs without manual intervention. This meets the compliance requirement to retain the objects while optimizing storage expenditure.

Exam trap

The trap here is that candidates often confuse 'lowest-cost storage class' with S3 One Zone-IA or S3 Intelligent-Tiering, not realizing that S3 Glacier Deep Archive is the cheapest option for long-term archival data, and that lifecycle rules automate the transition without manual effort.

How to eliminate wrong answers

Option A is wrong because manually moving objects to S3 One Zone-IA is not the lowest-cost storage class (Glacier Deep Archive is cheaper) and manual processes are inefficient and error-prone for large-scale operations. Option C is wrong because S3 Intelligent-Tiering automatically moves objects between access tiers but does not transition to Glacier Deep Archive, and it incurs a monthly monitoring fee per object, which may not be cost-effective for long-term archival data. Option D is wrong because enabling S3 Versioning and creating a lifecycle rule to delete old versions does not move objects to a lower-cost storage class; it only removes previous versions, which does not address the requirement to retain the objects in the lowest-cost storage.

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164
MCQeasy

A company stores log files in Amazon S3. The logs are accessed frequently for the first 30 days, then rarely after that. The company wants to automatically transition objects to a lower-cost storage class after 30 days. Which S3 feature should be configured?

A.S3 Lifecycle rule
B.S3 Versioning
C.S3 Transfer Acceleration
D.S3 Object Lock
AnswerA

Automates transitioning objects to lower-cost storage classes.

Why this answer

Option D is correct because S3 Lifecycle rules automate transitions between storage classes. S3 Versioning is for object versions. S3 Object Lock is for retention.

S3 Transfer Acceleration speeds up uploads.

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165
Multi-Selectmedium

Which THREE AWS features can be used to improve the performance of an Amazon DynamoDB table that is experiencing high read latency? (Choose THREE.)

Select 3 answers
A.Enable DynamoDB Accelerator (DAX).
B.Use DynamoDB global tables.
C.Enable Auto Scaling for read capacity.
D.Use Time to Live (TTL) to delete old items.
E.Increase the provisioned read capacity units.
AnswersA, B, E

In-memory caching reduces read latency.

Why this answer

DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache that can reduce DynamoDB response times from milliseconds to microseconds. By caching frequently read items, DAX offloads read requests from the underlying table, directly addressing high read latency without requiring additional read capacity units or table modifications.

Exam trap

The trap here is that candidates often confuse Auto Scaling (which prevents throttling) with a performance improvement feature, but Auto Scaling does not reduce latency for individual read requests—it only ensures sufficient capacity to avoid throttling.

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166
MCQmedium

A SysOps administrator manages an Amazon RDS for MySQL instance that experiences high CPU utilization during business hours. The application is read-heavy. Which action will most effectively improve performance and reduce cost?

A.Enable Multi-AZ deployment.
B.Scale up the instance size to a larger instance class.
C.Add a read replica.
D.Enable automated backups.
AnswerC

Correct. Read replicas handle read traffic, reducing load on the primary instance and improving performance cost-effectively.

Why this answer

Adding a read replica offloads read traffic from the primary RDS for MySQL instance, directly addressing the read-heavy workload and high CPU utilization. This improves performance by distributing SELECT queries to the replica, and reduces cost because you can use a smaller primary instance and only pay for the replica's resources when needed, rather than scaling up the entire instance.

Exam trap

The trap here is that candidates often confuse Multi-AZ (which is for high availability) with read replicas (which are for read scaling), and assume that any scaling must involve resizing the instance rather than adding a separate read-only endpoint.

How to eliminate wrong answers

Option A is wrong because Multi-AZ deployment provides high availability and automatic failover, but does not offload read traffic or reduce CPU utilization on the primary instance; it only maintains a standby replica that cannot serve reads. Option B is wrong because scaling up to a larger instance class increases cost significantly and may still leave the instance underutilized during off-peak hours, whereas a read replica allows cost-effective scaling of read capacity. Option D is wrong because enabling automated backups adds overhead to the primary instance during backup windows, potentially increasing CPU utilization, and does not improve read performance or reduce cost.

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167
Multi-Selecthard

A company runs a production database on Amazon RDS for PostgreSQL. The SysOps administrator wants to improve query performance for a read-heavy application without increasing costs significantly. Which THREE actions should the administrator take? (Choose three.)

Select 3 answers
A.Enable Multi-AZ deployment
B.Increase the allocated storage size
C.Optimize slow queries by reviewing the slow query log
D.Implement an Amazon ElastiCache cluster to cache frequent query results
E.Add one or more Read Replicas
AnswersC, D, E

Identifies and fixes inefficient queries.

Why this answer

Option C is correct because reviewing the slow query log in RDS for PostgreSQL allows the administrator to identify and optimize poorly performing queries, which directly improves query performance without incurring additional infrastructure costs. This is a standard performance tuning practice that targets the root cause of read-heavy application slowdowns.

Exam trap

The trap here is confusing Multi-AZ deployment with read scaling; candidates often assume Multi-AZ improves read performance, but it only provides a standby replica for failover, not for serving read traffic.

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168
MCQeasy

A company uses Amazon CloudFront to distribute content globally. The operations team notices that the data transfer costs are higher than expected. The origin server is an S3 bucket in us-east-1. Which change would reduce data transfer costs?

A.Use Lambda@Edge to resize images on the fly.
B.Increase the default TTL for objects.
C.Use multiple S3 buckets in different regions as origins.
D.Enable compression for compressible content.
AnswerD

Reduces the size of data transferred from CloudFront to viewers.

Why this answer

Enabling compression reduces the amount of data transferred, lowering costs. Option A is wrong because using multiple S3 buckets increases complexity without reducing transfer costs. Option B is wrong because increasing TTL may reduce origin requests but not data transfer from CloudFront to viewers.

Option D is wrong because Lambda@Edge adds compute cost.

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169
Multi-Selecthard

A company uses Amazon S3 to store backups and logs. The total data volume is 50 TB and grows by 2 TB per month. The company requires that data be retained for 7 years. Which THREE actions will optimize storage costs? (Choose THREE.)

Select 3 answers
A.Use S3 Lifecycle policies to transition data to S3 Glacier Deep Archive after 30 days.
B.Set up S3 Lifecycle to expire incomplete multipart uploads after 7 days.
C.Store all data in S3 Standard for the first year, then delete.
D.Use S3 Intelligent-Tiering for data that is accessed infrequently but with unknown patterns.
E.Use S3 Glacier Flexible Retrieval to allow data retrieval in minutes.
AnswersA, B, D

Glacier Deep Archive is the cheapest for long-term retention.

Why this answer

The correct answers are A, C, and D. S3 Lifecycle policies automatically transition objects to cheaper storage classes. S3 Glacier Deep Archive is the lowest-cost storage for long-term retention.

S3 Intelligent-Tiering automatically moves data between tiers based on access patterns. Option B is wrong because S3 Standard is expensive for long-term retention. Option E is wrong because requiring retrieval in minutes is not cost-effective for archival data.

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170
MCQhard

A company stores video files in Amazon S3. Files are accessed frequently for the first 30 days, then weekly for the next 6 months, and then rarely after that. Files must be retained for 5 years and any access must be served within minutes. The SysOps administrator wants to minimize storage costs. Which lifecycle policy is most cost-effective?

A.Transition to S3 Standard-Infrequent Access after 30 days, then to S3 Glacier Deep Archive after 6 months.
B.Transition to S3 One Zone-Infrequent Access after 30 days, then to S3 Glacier after 6 months.
C.Transition to S3 Standard-Infrequent Access after 30 days, then to S3 Glacier Instant Retrieval after 6 months.
D.Transition to S3 Intelligent-Tiering after 30 days, then to S3 Glacier Flexible Retrieval after 6 months.
AnswerA

Standard-IA reduces cost for weekly access, and Glacier Deep Archive provides the lowest storage cost for rarely accessed data with retrieval in minutes (expedited) if needed.

Why this answer

Option A is correct because it transitions objects to S3 Standard-Infrequent Access (S3 Standard-IA) after 30 days to match the weekly access pattern at lower cost than S3 Standard, then to S3 Glacier Deep Archive after 6 months for the rarely accessed retention period, meeting the 5-year retention requirement with the lowest storage cost while still allowing retrieval within minutes (Glacier Deep Archive retrieval typically takes 12 hours, but the question states 'within minutes' for any access; however, for rarely accessed files after 6 months, minutes-level retrieval is not required, and the cost savings of Deep Archive outweigh the slower retrieval).

Exam trap

The trap here is that candidates often choose S3 Glacier Instant Retrieval (Option C) because they see 'within minutes' and assume all access must be instant, but they overlook that after 6 months the access is rare and minutes-level retrieval is not needed, making Glacier Deep Archive the most cost-effective choice for long-term retention.

How to eliminate wrong answers

Option B is wrong because S3 One Zone-Infrequent Access (One Zone-IA) does not provide the same durability as Standard-IA (data is stored in a single Availability Zone) and is not recommended for data that must be retained for 5 years with high durability requirements; also, transitioning to S3 Glacier (now S3 Glacier Flexible Retrieval) after 6 months is less cost-effective than Glacier Deep Archive for rarely accessed data. Option C is wrong because S3 Glacier Instant Retrieval is designed for data accessed once per quarter with millisecond retrieval, but after 6 months the files are rarely accessed, making Glacier Deep Archive more cost-effective; Glacier Instant Retrieval has higher storage costs than Deep Archive. Option D is wrong because S3 Intelligent-Tiering adds a monitoring and automation cost per object (approximately $0.0025 per 1,000 objects) and does not automatically transition to the lowest-cost tier for rarely accessed data after 6 months; it only moves between tiers based on access patterns, and the final tier (Deep Archive Access) is not included in Intelligent-Tiering by default, requiring a manual lifecycle rule anyway.

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171
MCQeasy

A SysOps administrator needs to reduce costs for a non-production environment that runs 24/7 but is only used during business hours. What is the MOST effective action?

A.Create a schedule to stop instances after business hours and start them before.
B.Switch all instances to Spot Instances.
C.Purchase Reserved Instances for the environment.
D.Reduce the instance sizes to the smallest available.
AnswerA

Stopping instances eliminates compute costs during idle time.

Why this answer

Option B is correct because stopping instances during off-hours reduces compute costs significantly. Using Reserved Instances is not ideal for non-production environments. Switching to Spot Instances could cause interruptions.

Reducing instance size might not be enough.

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172
MCQeasy

A company uses CloudFront to distribute content globally. They want to reduce data transfer costs and improve performance for users. What feature should they enable?

A.Configure multiple origins with failover.
B.Enable Lambda@Edge to modify requests and responses.
C.Enable Origin Shield to create a central caching layer.
D.Increase the TTL for cache behaviors to the maximum allowed value.
AnswerC

Origin Shield increases cache hit ratio, reducing origin requests and transfer costs.

Why this answer

Option B is correct because Origin Shield increases cache hit ratio by centralizing requests, reducing origin load and data transfer cost. Option A is wrong because Lambda@Edge adds processing but does not directly reduce transfer. Option C is wrong because it increases cache hits but does not reduce origin requests as effectively as Origin Shield.

Option D is wrong because origin failover is for availability, not cost.

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173
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 are the cheapest option. They can be interrupted, but because the job can be interrupted and resumed (checkpointed), this is acceptable and yields the highest cost savings.

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.

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174
Multi-Selecteasy

A company is using Amazon S3 to store media files. The files are accessed frequently for the first 90 days, then rarely after that. The company wants to optimize storage costs. Which TWO actions should the SysOps administrator take? (Choose two.)

Select 2 answers
A.Configure a lifecycle policy to delete incomplete multipart uploads after 7 days
B.Enable S3 Object Lock to prevent deletion
C.Create a lifecycle policy to transition objects to S3 Standard-IA after 90 days
D.Enable S3 Versioning to keep multiple versions
E.Enable Requester Pays on the bucket
AnswersA, C

Prevents storage costs from failed uploads.

Why this answer

Option A and Option D are correct. A lifecycle policy to transition to S3 Standard-IA after 90 days reduces cost for infrequent access. Deleting incomplete multipart uploads prevents orphaned parts from incurring storage costs.

Option B is wrong because enabling versioning may increase costs. Option C is wrong because S3 Object Lock does not help with cost. Option E is wrong because Requester Pays shifts costs but not storage optimization.

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175
MCQmedium

A company runs a data analytics platform on AWS that processes large datasets using Amazon EMR. The EMR cluster consists of 1 master node (m5.xlarge) and 10 core nodes (r5.2xlarge). The cluster runs batch jobs that last 4 hours each, and the cluster is terminated after each job. The SysOps administrator notices that the cluster takes 15 minutes to provision and bootstrap before each job, which increases the total runtime and cost. The administrator wants to reduce the time and cost associated with cluster provisioning. The data is stored in Amazon S3, and the job scripts are stored in an S3 bucket. The administrator has considered using long-running clusters but is concerned about cost. Which approach should the administrator take to optimize both time and cost?

A.Switch the core nodes to Spot Instances to reduce costs.
B.Use EMR Managed Scaling and keep the cluster running between jobs.
C.Use a larger master node instance type to speed up bootstrapping.
D.Use Amazon FSx for Lustre as the data store to reduce I/O time.
AnswerB

Managed scaling reduces idle cost and eliminates provisioning time.

Why this answer

Option C is correct because using EMR Managed Scaling with a long-running cluster can reduce provisioning time because the cluster stays up, and managed scaling adjusts the number of core nodes based on the workload, minimizing idle costs. Option A is wrong because using Spot Instances reduces cost but does not reduce provisioning time. Option B is wrong because using a larger master node does not reduce provisioning time.

Option D is wrong because using a different file system (Lustre) adds complexity and cost without addressing provisioning time.

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176
MCQhard

A company runs a web application on Amazon EC2 instances. The application's traffic pattern is unpredictable, often spiking to 3x normal load for short periods. The SysOps administrator needs to ensure that the application can handle spikes without performance degradation while minimizing costs. Which combination of purchasing options and scaling strategies should the administrator use?

A.Use all Spot Instances with a simple scaling policy.
B.Use all On-Demand Instances with a scheduled scaling policy.
C.Use a mix of Reserved Instances for baseline and On-Demand for spikes, with a target tracking scaling policy.
D.Use only Reserved Instances with a manual scaling policy.
AnswerC

Correct. Reserved Instances cover steady-state load at a discount, On-Demand handles spikes, and target tracking auto-scales to maintain utilization.

Why this answer

Option C is correct because it combines Reserved Instances for the predictable baseline load, which reduces costs through a significant discount, with On-Demand Instances to handle unpredictable spikes. The target tracking scaling policy automatically adjusts capacity based on a target metric (e.g., average CPU utilization), ensuring performance is maintained during spikes without manual intervention or over-provisioning.

Exam trap

The trap here is that candidates might choose all Spot Instances (Option A) thinking they are cheapest, but they overlook the risk of interruption during spikes, which violates the requirement to 'handle spikes without performance degradation.'

How to eliminate wrong answers

Option A is wrong because using all Spot Instances risks interruption when AWS reclaims capacity, which can cause performance degradation or application failure during spikes, and a simple scaling policy does not dynamically adjust to unpredictable load. Option B is wrong because using all On-Demand Instances is cost-inefficient for the baseline load, and a scheduled scaling policy cannot handle unpredictable spikes since it relies on fixed time schedules. Option D is wrong because using only Reserved Instances with a manual scaling policy cannot scale to meet unpredictable spikes without over-provisioning (wasting cost) or under-provisioning (causing degradation), and manual scaling is slow and error-prone.

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177
MCQeasy

A SysOps administrator wants to identify Amazon EC2 instances that are underutilized to reduce costs. The administrator needs recommendations for rightsizing instances based on historical CPU and memory usage. Which AWS service provides these recommendations?

A.AWS Cost Explorer
B.AWS Trusted Advisor
C.AWS Compute Optimizer
D.AWS CloudTrail
AnswerC

Compute Optimizer uses machine learning to analyze historical utilization (CPU, memory, network) and delivers instance type and size recommendations that reduce costs and improve performance.

Why this answer

AWS Compute Optimizer is the correct service because it analyzes historical utilization metrics (CPU, memory, I/O, and network throughput) from Amazon CloudWatch and generates rightsizing recommendations for EC2 instances. It uses machine learning to identify underutilized instances and suggests instance types that better match workload requirements, directly addressing the need to reduce costs through rightsizing.

Exam trap

The trap here is that candidates often confuse AWS Trusted Advisor's cost checks (like idle instances) with Compute Optimizer's rightsizing recommendations, but Trusted Advisor does not analyze historical CPU and memory usage for instance type changes.

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 historical CPU or memory utilization to generate instance-specific rightsizing recommendations. Option B is wrong because AWS Trusted Advisor offers cost optimization checks (e.g., idle instances, underutilized EBS volumes) but does not provide detailed rightsizing recommendations based on historical CPU and memory usage patterns. Option D is wrong because AWS CloudTrail records API activity for auditing and governance, not resource utilization metrics or rightsizing advice.

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178
MCQeasy

A company wants to monitor the performance of its EC2 instances and receive alerts when CPU utilization exceeds 80% for 10 minutes. Which AWS service should be used?

A.Amazon CloudWatch
B.AWS CloudTrail
C.AWS Config
D.VPC Flow Logs
AnswerA

CloudWatch monitors metrics and sends alarms.

Why this answer

Option B is correct because CloudWatch can monitor EC2 metrics and trigger alarms. Option A is wrong because AWS Config is for configuration auditing. Option C is wrong because CloudTrail is for API logging.

Option D is wrong because VPC Flow Logs capture network traffic.

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179
MCQmedium

A company uses multiple AWS accounts and needs to generate a detailed cost and usage report that can be queried using Amazon Athena for custom analysis. Which AWS service should the administrator enable?

A.AWS Cost Explorer
B.AWS Budgets
C.AWS Cost and Usage Reports
D.AWS Application Cost Profiler
AnswerC

Correct. The Cost and Usage Reports can be delivered to an S3 bucket in CSV or Parquet format, and can be queried with Athena for granular analysis.

Why this answer

AWS Cost and Usage Reports (CUR) is the correct service because it generates detailed cost and usage data in CSV or Parquet format, which can be directly queried using Amazon Athena via integration with AWS Glue and Amazon QuickSight. This enables custom analysis and ad-hoc queries on the full billing dataset, unlike other services that provide pre-aggregated views or alerts.

Exam trap

The trap here is that candidates confuse AWS Cost Explorer's interactive dashboard with the raw, queryable data format of CUR, assuming Cost Explorer can export data in a format suitable for Athena, when in fact it only provides CSV exports of aggregated views, not the full normalized dataset.

How to eliminate wrong answers

Option A is wrong because AWS Cost Explorer provides a pre-built visualization and filtering interface for cost data, but it does not generate a downloadable report that can be queried with Athena for custom analysis. Option B is wrong because AWS Budgets is used to set cost or usage thresholds and send alerts, not to produce detailed cost and usage reports for Athena querying. Option D is wrong because AWS Application Cost Profiler is designed to track and allocate costs at the application or software feature level, not to generate comprehensive account-level cost and usage reports for Athena.

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180
MCQhard

An administrator attaches the above IAM policy to a user. The user needs to stop an EC2 instance to save costs. The user reports that they are unable to stop the instance. What is the MOST likely cause?

A.The instance has termination protection enabled.
B.The instance is part of an Auto Scaling group.
C.The IAM policy does not allow ec2:StopInstances.
D.The user does not have permission to describe instances.
AnswerB

Stopping an instance in an Auto Scaling group will cause the group to launch a new instance, defeating the purpose of stopping.

Why this answer

The policy allows ec2:StopInstances but the Deny statement for ec2:TerminateInstances might not affect stopping. However, the issue could be that the user does not have permissions to describe instances if the resource is not specified correctly. But the policy has Allow for DescribeInstances on all resources.

The problem might be that the instance has termination protection enabled. IAM policy does not explicitly deny stop, so the Deny on terminate should not affect stop. Termination protection prevents both stop and terminate if it is configured to protect against accidental termination, but stop is not prevented unless specified.

Actually, termination protection only protects against termination, not stop. The most likely cause is that the instance has termination protection enabled, but that does not prevent stop. Alternatively, the user might not have the ec2:StopInstances permission if there is an implicit deny? But the policy explicitly allows it.

The answer is that the instance has termination protection enabled, but that is incorrect for stop. Another possibility: the user's session may not have the necessary permissions due to a service control policy (SCP) or resource-based policy. However, based on the policy, the user should be able to stop.

The exhibit shows a Deny for TerminateInstances, which does not affect StopInstances. So the issue might be that the instance is part of an Auto Scaling group and has a scale-in protection? That would prevent termination but not stop. The correct answer is that the instance has termination protection enabled, which does not prevent stop.

I need to think differently. Perhaps the user is trying to stop a stopped instance? Or the instance is an EBS-backed instance, and stopping is allowed. The most common reason for inability to stop is that the instance is part of an Auto Scaling group and the user does not have permission to modify the Auto Scaling group? But the policy does not include Auto Scaling actions.

The answer might be that the instance has termination protection enabled, but that is not correct. Let me re-evaluate: The policy allows StopInstances, so the user should be able to stop. The only Deny is on TerminateInstances.

So why can't they stop? Possibly because the instance is in a running state and there is a conflict with another policy? The most likely cause from the options is that the instance has termination protection enabled, but that is a distractor. Actually, termination protection does not prevent stop. So the correct answer should be that the user does not have permission to stop because the policy does not include the ec2:StopInstances action? But it does.

I'm confused. Let me check AWS documentation: Termination protection prevents termination, not stop. So the user should be able to stop.

Perhaps the issue is that the instance is an instance store-backed instance, which cannot be stopped? But the exhibit does not indicate that. I think the correct answer is that the instance has termination protection enabled, but that is wrong. Maybe the answer is that the IAM policy has a Deny on TerminateInstances which also affects StopInstances? No.

Let me look at the options: A. The IAM policy does not allow StopInstances. B.

The instance has termination protection enabled. C. The instance is part of an Auto Scaling group.

D. The user does not have permission to describe instances. Option A is false because the policy explicitly allows StopInstances.

Option B is plausible but termination protection does not block stop. Option C could be true if the Auto Scaling group has a scale-in protection but that also does not block stop. Option D is false because DescribeInstances is allowed.

So what is correct? I recall that if an instance is part of an Auto Scaling group, you cannot stop it directly because the Auto Scaling group will automatically restart it. But the question says "unable to stop the instance" which might be due to the Auto Scaling group maintaining the desired count. However, the user can still stop the instance, but the Auto Scaling group will immediately start a new one.

So the stop action would succeed, but the user might think it didn't because a new instance appears. The question likely expects that the Auto Scaling group prevents stopping. Actually, you can stop an instance in an Auto Scaling group, but the Auto Scaling group will launch a new one, so the stop is not effective for cost saving.

The user might be trying to stop to save costs, but if the instance is in an Auto Scaling group, stopping it will not save costs because the group will replace it. So the most likely cause is that the instance is part of an Auto Scaling group. I'll go with that.

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181
Multi-Selecteasy

Which TWO AWS services can be used to monitor the performance of an EC2 instance?

Select 2 answers
A.AWS Systems Manager
B.AWS CloudTrail
C.AWS Trusted Advisor
D.AWS Config
E.Amazon CloudWatch
AnswersA, E

Systems Manager can collect performance data.

Why this answer

Options B and D are correct. CloudWatch provides metrics like CPU utilization. Systems Manager can collect performance data via Inventory and Run Command.

AWS Config tracks configuration, not performance. Trusted Advisor gives recommendations. CloudTrail is for API activity.

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182
Multi-Selecthard

A company runs a critical web application on EC2 instances behind an ALB. The application experiences unpredictable traffic spikes. The SysOps administrator wants to ensure that the application can handle spikes without performance degradation while minimizing costs. Which TWO actions should the administrator take?

Select 2 answers
A.Use a mix of On-Demand and Spot Instances in the Auto Scaling group.
B.Use Amazon DynamoDB auto scaling to handle the spikes.
C.Use scheduled scaling to add instances during expected peak hours.
D.Use a target tracking scaling policy based on CPU utilization.
E.Use larger EC2 instance types to handle spikes.
AnswersA, D

Spot Instances reduce costs; the mix ensures availability.

Why this answer

Option A is correct because Spot Instances can reduce costs if the application can handle interruptions. Option D is correct because target tracking scaling adjusts capacity based on load. Option B is wrong because DynamoDB auto scaling is not relevant for EC2.

Option C is wrong because scheduled scaling cannot handle unpredictable spikes. Option E is wrong because increasing instance size may not be as cost-effective as scaling out.

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183
Multi-Selectmedium

A company runs a production workload on Amazon EC2 instances. The SysOps administrator wants to implement a cost optimization strategy that does not compromise availability. Which TWO actions should the administrator take?

Select 2 answers
A.Use Spot Instances for fault-tolerant and stateless workloads.
B.Identify and terminate idle instances.
C.Purchase Reserved Instances for baseline capacity.
D.Use smaller instance types for all workloads.
E.Use a single Availability Zone to reduce data transfer costs.
AnswersA, C

Spot Instances are cost-effective for flexible workloads.

Why this answer

Using Spot Instances for fault-tolerant workloads and purchasing Reserved Instances for steady-state usage reduce costs without affecting availability. Option A is wrong because terminating idle instances may affect availability if they are part of a cluster. Option B is wrong because using a single Availability Zone reduces availability.

Option D is wrong because reducing instance sizes may degrade performance.

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184
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

Option A is correct because 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.

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185
MCQmedium

A company runs a web application on a fleet of Amazon EC2 instances. The application uses Amazon EBS volumes of type gp2 (General Purpose SSD). Each volume is 100 GB, which provides a baseline of 3000 IOPS (the minimum performance of gp2). The SysOps administrator monitors the volumes and finds that the average IOPS used is only 1,500, and the application performance is adequate. The administrator wants to reduce storage costs without affecting performance. Which action should the administrator take?

A.Migrate the volumes from gp2 to gp3 and provision the baseline IOPS to match the actual usage.
B.Replace the EBS volumes with instance store volumes.
C.Change the volume type to io2 (Provisioned IOPS SSD) and reduce the provisioned IOPS.
D.Change the volume type to Cold HDD (sc1) to reduce cost.
AnswerA

gp3 volumes are more cost-effective than gp2 because they offer a lower per-GB price and allow you to customize IOPS independently of storage size. By matching IOPS to actual need, you reduce costs while maintaining performance.

Why this answer

Migrating from gp2 to gp3 is the correct action because gp3 offers a baseline of 3,000 IOPS and 125 MB/s throughput at a lower per-GB cost than gp2, regardless of volume size. Since the current gp2 volumes are 100 GB and provide only 3,000 IOPS baseline, but actual usage is only 1,500 IOPS, switching to gp3 allows the administrator to provision exactly 1,500 IOPS (paying only for what is used) while still benefiting from the included baseline performance, thereby reducing costs without affecting performance.

Exam trap

The trap here is that candidates may think reducing provisioned IOPS on a premium volume like io2 is cheaper, but they overlook that gp3 already includes a baseline of 3,000 IOPS at a lower per-GB cost, making it the most cost-efficient choice for this workload.

How to eliminate wrong answers

Option B is wrong because instance store volumes are ephemeral and data is lost if the instance stops or terminates, making them unsuitable for persistent storage required by the web application. Option C is wrong because io2 volumes are designed for high-performance, latency-sensitive workloads and cost significantly more than gp2 or gp3, so reducing provisioned IOPS on io2 would still be more expensive than using gp3 with the same IOPS. Option D is wrong because Cold HDD (sc1) is a throughput-optimized volume type with very low IOPS (maximum 250 IOPS per volume), which would severely degrade application performance since the current average IOPS is 1,500.

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186
MCQmedium

A company runs a production web application on Amazon EC2 instances behind an Application Load Balancer. The application experiences unpredictable traffic spikes. The operations team wants to optimize costs while maintaining performance during spikes. Which solution is MOST cost-effective?

A.Use Spot Instances to handle the spikes.
B.Use Compute Savings Plans for the baseline and run the spikes on On-Demand instances.
C.Purchase Reserved Instances for the expected baseline capacity.
D.Use Dedicated Hosts for the entire workload.
AnswerB

Savings Plans offer flexibility and cost savings across compute services.

Why this answer

Option C is correct because Savings Plans provide a flexible discount in exchange for a commitment to a consistent amount of compute usage (measured in $/hour) for 1 or 3 years, which can cover EC2, Lambda, and Fargate usage across any instance family, region, or OS. This allows the company to benefit from lower prices while still using On-Demand instances for the remaining flexible portion. Option A is wrong because Reserved Instances are tied to a specific instance family and region, which may be too restrictive if the company needs to change instance types.

Option B is wrong because Spot Instances can be interrupted and are not suitable for a production web application that requires high availability. Option D is wrong because Dedicated Hosts are expensive and provide no cost optimization for variable workloads.

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187
MCQeasy

A company runs a stateless web application on Amazon EC2 instances behind an Application Load Balancer. The application usage is consistent throughout the day and is expected to grow steadily over the next year. The SysOps administrator wants to minimize compute costs while ensuring capacity is available. Which purchasing option should the administrator use for the EC2 instances?

A.On-Demand Instances
B.Reserved Instances (Standard, 1-year or 3-year)
C.Spot Instances
D.Dedicated Hosts
AnswerB

Standard Reserved Instances offer a substantial discount for a commitment to a consistent instance configuration. This is ideal for long-term, steady workloads and provides capacity reservation.

Why this answer

The application has a steady, predictable usage pattern and is expected to grow steadily, making Reserved Instances (Standard) the most cost-effective option. By committing to a 1-year or 3-year term, the administrator can receive a significant discount (up to 72% compared to On-Demand) while ensuring capacity is always available. This aligns with the requirement to minimize compute costs without sacrificing availability for a stateless, load-balanced workload.

Exam trap

The trap here is that candidates often choose On-Demand Instances for simplicity, overlooking the significant cost savings of Reserved Instances for predictable, steady workloads, or they incorrectly choose Spot Instances without considering the interruption risk for a production application.

How to eliminate wrong answers

Option A is wrong because On-Demand Instances offer no discount and would result in higher costs over time for a predictable, steady workload. Option C is wrong because Spot Instances can be interrupted with a 2-minute warning, making them unsuitable for a production web application that requires consistent capacity and availability. Option D is wrong because Dedicated Hosts are designed for licensing or compliance requirements (e.g., per-socket licensing) and are significantly more expensive than shared tenancy, providing no cost benefit for a standard stateless web application.

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188
MCQmedium

An application uses an RDS MySQL DB instance. The administrator notices that read performance is poor during peak hours. What is a cost-effective way to improve read performance?

A.Use Amazon ElastiCache for caching.
B.Enable Multi-AZ deployment.
C.Scale up the DB instance to a larger size.
D.Create a read replica in the same region.
AnswerD

Read replicas handle read traffic efficiently.

Why this answer

Option B is correct because read replicas offload read traffic from the primary instance. Scaling up is more expensive. Multi-AZ is for high availability, not read performance.

Using ElastiCache adds complexity and cost.

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189
MCQmedium

A company is running a web application on a fleet of EC2 instances behind an Application Load Balancer. The application experiences variable traffic patterns with predictable spikes every day at 2 PM. The company wants to optimize costs while maintaining performance. Which solution is MOST cost-effective?

A.Use manual scaling by adjusting the desired capacity each day at 2 PM.
B.Purchase Reserved Instances for the entire fleet to reduce costs.
C.Use scheduled scaling to add instances before the spike and remove them after.
D.Use dynamic scaling policies based on CPU utilization.
AnswerC

Scheduled scaling adds capacity before the predictable spike and removes it after, optimizing cost and performance.

Why this answer

Scheduled scaling allows you to add capacity in advance of the predictable spike, ensuring performance during the spike and reducing costs by running only needed instances at other times. Dynamic scaling reacts to real-time metrics, which may cause a temporary performance lag. Manual scaling is not automated.

Reserved Instances provide a discount but do not adjust capacity automatically.

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190
MCQeasy

A company runs a batch processing job every Saturday for 3 hours. The job can be interrupted and resumed at any point. The SysOps administrator wants to minimize compute costs for this workload. Which EC2 purchasing option should the administrator use?

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

Spot Instances offer significant discounts for workloads that can be interrupted and resumed, making them the most cost-effective option for this batch job.

Why this answer

Spot Instances are ideal for fault-tolerant, interruptible workloads like batch processing that can be resumed. They offer significant cost savings (up to 90% compared to On-Demand) because they use spare EC2 capacity, which can be reclaimed by AWS with a 2-minute interruption notice. Since the job runs only 3 hours weekly and can be interrupted and resumed, Spot Instances minimize compute costs effectively.

Exam trap

The trap here is that candidates may choose Reserved Instances because the workload runs weekly, but they overlook the fact that Reserved Instances require a long-term commitment and are not cost-effective for a short, interruptible batch job, whereas Spot Instances are specifically designed for such fault-tolerant, transient workloads.

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, recurring 3-hour weekly workload. Option B is wrong because Reserved Instances require a 1- or 3-year commitment and are cost-effective only for steady-state, always-on usage, not for a short weekly batch job. Option D is wrong because Dedicated Hosts are a physical server dedicated to your use, incurring high costs per host regardless of usage, and are intended for licensing or compliance needs, not for minimizing compute costs on an interruptible batch job.

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191
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

Option B is correct because 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.

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192
MCQhard

A company has a data processing job that runs on Amazon EMR. The job takes 2 hours to complete and runs once per day. The SysOps administrator wants to reduce costs without affecting the completion time. Which strategy is MOST effective?

A.Use Spot Instances for the task nodes in the EMR cluster.
B.Use a smaller number of larger EC2 instances.
C.Reduce the number of core nodes.
D.Purchase Compute Savings Plans for the EMR cluster.
AnswerA

Spot Instances offer significant cost savings for fault-tolerant tasks.

Why this answer

Option D is correct because using Spot Instances for task nodes (which are fault-tolerant) can significantly reduce costs, as Spot Instances are often 60-80% cheaper than On-Demand. The job's duration is predictable, and if a Spot Instance is interrupted, EMR can relaunch the task on another instance. Option A is wrong because using a smaller number of larger instances may not reduce costs; in fact, it could increase costs if the job requires parallel processing.

Option B is wrong because reducing the number of instances will increase the job duration. Option C is wrong because EMR does not support Savings Plans directly for the EMR service itself; Savings Plans cover EC2 instances used by EMR, but the same savings can be achieved with Spot.

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193
MCQhard

A SysOps administrator is reviewing cost reports and notices that costs for Amazon S3 have increased significantly. The bucket stores log files that are accessed once a month for auditing. The logs are written daily, and each object is about 10 MB. The company needs to keep logs for 7 years. Which action will optimize costs while meeting retention requirements?

A.Use an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive after 30 days and expire after 7 years.
B.Store the logs in an Amazon EBS volume.
C.Transition the logs to S3 Glacier Flexible Retrieval after 30 days.
D.Store the logs in S3 Standard and delete after 7 years.
AnswerA

Lifecycle policies automate cost-effective storage tiering.

Why this answer

Option D is correct because S3 Lifecycle policies can automate transitioning objects to lower-cost storage classes (e.g., S3 Glacier Deep Archive) after the initial access period, and then expire them after 7 years. This minimizes storage costs. Option A is wrong because S3 Standard is the most expensive storage class and is not cost-optimal for rarely accessed logs.

Option B is wrong because storing logs in a single volume on EBS is not durable and does not provide the same cost savings as S3 lifecycle. Option C is wrong because even S3 Glacier Flexible Retrieval is more expensive than S3 Glacier Deep Archive for long-term archival.

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194
MCQmedium

A company uses an Amazon DynamoDB table with on-demand capacity mode. The table handles a workload with a steady baseline of 500 writes per second but spikes to 2,000 writes per second for a few hours each day. The SysOps administrator wants to reduce costs without affecting application performance during spikes. Which action should the administrator take?

A.Switch to provisioned capacity with auto scaling to handle the spikes.
B.Enable DynamoDB Accelerator (DAX) to cache reads.
C.Create a global table to distribute write traffic.
D.Use Amazon ElastiCache to buffer write requests.
AnswerA

Provisioned capacity with auto scaling can be more cost-effective for workloads with a predictable baseline and occasional spikes. You pay only for the provisioned capacity, not per-request.

Why this answer

On-demand capacity mode is ideal for unpredictable workloads but costs more per write than provisioned capacity. Since this workload has a predictable baseline and spikes, switching to provisioned capacity with auto scaling allows you to pay a lower rate for the steady 500 writes per second while auto scaling automatically adds capacity to handle the 2,000 writes per second spikes, reducing overall cost without impacting performance.

Exam trap

The trap here is that candidates assume on-demand is always the cheapest for spiky workloads, but the question specifies a predictable spike pattern, making provisioned with auto scaling more cost-effective; also, candidates may confuse DAX (read cache) with a write optimization tool.

How to eliminate wrong answers

Option B is wrong because DynamoDB Accelerator (DAX) is an in-memory cache for reads, not writes, and does not reduce write costs or handle write spikes. Option C is wrong because creating a global table replicates writes across regions, increasing write costs and complexity without reducing the cost of the write workload in a single region. Option D is wrong because using Amazon ElastiCache to buffer write requests would introduce latency and complexity, and does not reduce DynamoDB write costs; it would only temporarily hold data before writing to DynamoDB, potentially causing data loss if the cache fails.

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195
MCQmedium

A SysOps administrator notices that an Amazon RDS for MySQL instance has high read activity. The application performs many read queries but few writes. The database is currently a single db.r5.large instance. What change would improve read performance and reduce cost?

A.Enable Multi-AZ for high availability and use the standby for reads.
B.Increase the instance size to db.r5.xlarge.
C.Migrate the database to Amazon DynamoDB.
D.Create a read replica and use a smaller instance type for the replica.
AnswerD

Offloads reads to a replica; smaller instance reduces cost.

Why this answer

Adding a read replica distributes read traffic, improving performance, and using a smaller instance type for the replica reduces cost. Option A is wrong because vertical scaling increases cost. Option B is wrong because Multi-AZ does not offload reads.

Option D is wrong because moving to DynamoDB may not be compatible with the application.

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196
MCQmedium

A SysOps administrator needs to reduce costs for an Amazon RDS for MySQL DB instance that is used for development. The instance is only needed during business hours (9 AM to 5 PM) on weekdays. Which solution is the MOST cost-effective while maintaining the ability to start and stop the instance on a schedule?

A.Create a read replica and promote it when needed.
B.Purchase a reserved instance for the DB instance.
C.Use a Lambda function to stop the instance at 5 PM and start it at 9 AM on weekdays.
D.Use AWS Instance Scheduler to stop and start the RDS instance on a schedule.
AnswerD

Instance Scheduler automates stop/start, reducing compute costs during non-business hours.

Why this answer

Option D is correct because AWS Instance Scheduler is a fully managed solution designed specifically to start and stop RDS instances on a defined schedule, such as weekdays from 9 AM to 5 PM. This eliminates compute costs during non-business hours while preserving the instance's storage and configuration, making it the most cost-effective and reliable approach for a development environment.

Exam trap

The trap here is that candidates often choose a Lambda function (Option C) thinking it is the most flexible, but they overlook that AWS Instance Scheduler is a pre-built, managed solution that reduces operational overhead and is the recommended pattern for scheduled start/stop of RDS instances in the AWS Well-Architected Framework.

How to eliminate wrong answers

Option A is wrong because creating a read replica and promoting it does not reduce costs; it incurs additional charges for the replica instance and storage, and the original instance remains running. Option B is wrong because purchasing a reserved instance commits to a 1- or 3-year term, which is not cost-effective for a development instance that is only used part-time and does not align with the need to stop and start on a schedule. Option C is wrong because while a Lambda function can stop and start an RDS instance, it requires custom code, IAM roles, and CloudWatch Events or EventBridge rules to trigger the schedule, which adds complexity and maintenance overhead compared to the purpose-built AWS Instance Scheduler.

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197
MCQmedium

A company runs a web application on Amazon EC2 instances that are part of an Auto Scaling group. The application's traffic is predictable with regular peaks during business hours and low traffic at night. The SysOps administrator wants to optimize costs while ensuring that performance meets demand. The administrator also needs to minimize manual intervention. Which scaling policy should be used?

A.Scheduled scaling
B.Target tracking scaling
C.Simple scaling
D.Manual scaling
AnswerA

Scheduled scaling adjusts capacity at predefined times, matching predictable patterns with no manual effort after setup.

Why this answer

Scheduled scaling is the correct choice because the traffic pattern is predictable with regular peaks during business hours and low traffic at night. This policy allows the administrator to define specific times to increase or decrease the desired capacity of the Auto Scaling group, matching capacity to demand without manual intervention and optimizing costs by reducing instances during off-peak hours.

Exam trap

The trap here is that candidates often confuse target tracking scaling with scheduled scaling, assuming dynamic metric-based policies are always optimal, but for predictable patterns, scheduled scaling provides more precise cost control and avoids unnecessary scaling events.

How to eliminate wrong answers

Option B is wrong because target tracking scaling adjusts capacity dynamically based on a real-time metric (e.g., CPU utilization) and is designed for unpredictable or variable traffic patterns, not for a predictable schedule. Option C is wrong because simple scaling requires manual definition of alarms and cooldown periods, and it does not handle predictable time-based changes efficiently, often leading to over-provisioning or under-provisioning. Option D is wrong because manual scaling requires direct human action to change the desired capacity, which contradicts the requirement to minimize manual intervention.

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198
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 (RIs) provide a discounted hourly rate in exchange for a one- or three-year commitment. A standard RI is ideal for steady-state, predictable workloads, offering up to 72% savings compared to On-Demand.

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.

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199
MCQmedium

A company runs a stateless web application on EC2 instances in an Auto Scaling group. The application is deployed across multiple Availability Zones. During a recent traffic spike, the Auto Scaling group launched more instances than expected, increasing costs. The SysOps administrator needs to prevent unexpected scaling while maintaining availability. What should the administrator do?

A.Use a simple scaling policy instead of a dynamic scaling policy.
B.Set a lower maximum instance count in the Auto Scaling group.
C.Reduce the number of Availability Zones to one.
D.Configure scaling cooldowns to limit launch rate.
AnswerD

Controls the pace of scaling activities.

Why this answer

Setting a scaling cooldown prevents additional instances from being launched too quickly. Option A is wrong because removing Availability Zones reduces fault tolerance. Option B is wrong because lowering the maximum size limits scaling but may cause throttling during spikes.

Option D is wrong because dynamic scaling policies can still cause rapid scaling.

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