85 practice questions for Domain 4 of the AWS Certified Solutions Architect - Associate (SAA-C03) exam, which makes up 20% of its scored content. Your answers count towards one score and one timer for the whole exam.
Domain 4: Design Cost-Optimized Architectures
172. Objects in Amazon S3 are accessed frequently for 30 days, rarely for the next 90 days, and almost never afterwards. All objects must be retained. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: B. A well-understood, time-based access pattern is cheapest to handle with explicit transitions to progressively colder classes while retaining the data. Expiring objects at 120 days violates the retention requirement. Keeping everything in Standard pays frequent-access rates for rarely touched data, and Versioning increases stored volume. Intelligent-Tiering adds a monitoring charge and suits unpredictable rather than well-understood patterns.
173. An Amazon S3 bucket holds 200 TB of objects whose access patterns are irregular and differ unpredictably from object to object. Which solution meets these requirements at the lowest cost without introducing retrieval delays?
Answer and explanation
Answer: A. Intelligent-Tiering moves objects between access tiers based on observed usage with no retrieval fee or delay, which suits unpredictable per-object patterns at this scale. Standard-IA charges retrieval fees and early-deletion penalties on objects that turn out to be accessed often. Glacier Flexible Retrieval introduces restore times of minutes to hours. A blanket transition applies one assumption to objects with differing patterns.
174. An archive of 40 TB must be retained for ten years, is expected to be retrieved at most once, and can tolerate a retrieval time of twelve hours. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: C. Deep Archive has the lowest storage price of any S3 class and is designed for decade-scale retention with retrieval measured in hours, which the twelve-hour tolerance accommodates. Glacier Instant Retrieval costs more for millisecond access that is not needed. Standard-IA is priced for occasional immediate access. One Zone-IA reduces durability and still costs far more than Deep Archive.
175. External research partners download a large Amazon S3 dataset, and the bucket owner must not bear the request and data transfer charges. Which solution meets these requirements?
Answer and explanation
Answer: A. Requester Pays shifts request and data transfer charges to the authenticated requester rather than the bucket owner. A rate-limiting policy controls usage without changing who pays. Replication moves the cost to the owner in another Region. Transfer Acceleration adds cost rather than reallocating it.
176. Amazon EBS snapshots have accumulated over several years, and cost must be reduced without losing required recovery points. Which combination of steps meets these requirements? (Select TWO.)
Answer and explanation
Answer: C, E. Lifecycle policies enforce retention automatically, and the archive tier stores rarely needed snapshots at substantially lower cost while keeping them restorable. Blanket deletion may destroy required recovery points. Creating images adds artifacts rather than reducing cost. EBS snapshots are not customer-visible S3 objects and cannot be moved manually to a Glacier class.
177. An organization requires visibility into Amazon S3 storage usage and activity across many accounts to identify cost optimization opportunities. Which solution meets these requirements?
Answer and explanation
Answer: B. Storage Lens aggregates usage and activity metrics across accounts and buckets with recommendations, which is what organization-wide optimisation requires. Access logging records individual requests per bucket and requires separate analysis. Config tracks configuration compliance. Per-bucket dashboards lack cross-account aggregation and recommendations.
178. An application must retain seven years of log files that are rarely retrieved, and a retrieval latency of several hours is acceptable. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: A. Deep Archive has the lowest storage price and is designed for data retained for years and accessed once or twice, with retrieval measured in hours, which matches both the retention and the tolerated latency. Standard is priced for frequent access. Standard-IA suits infrequent access that still needs millisecond retrieval. Intelligent-Tiering adds a monitoring charge for a pattern that is already well understood.
179. A development environment of Amazon EC2 instances is required only during business hours from Monday to Friday. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: A. Stopped EC2 instances incur no instance charges, so scheduling shutdown outside business hours removes roughly two-thirds of the cost with no architectural change. Reserved Instances commit to continuous usage the workload does not need. A smaller instance still pays for idle hours. Dedicated Hosts carry a premium for isolation this environment does not require.
180. An image-rendering job runs for several hours each night, can be interrupted at any point, and resumes from a checkpoint. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: D. Interruption-tolerant batch work is the ideal Spot workload and a mixed instances policy spreads across pools to reduce interruption impact. On-Demand is the baseline price. Reserved Instances commit to continuous usage that a few hours nightly would not efficiently consume. Dedicated Instances add a premium for hardware isolation the job does not require.
181. An organization with 40 AWS accounts wants volume pricing tiers applied across the whole estate and Savings Plans benefits shared between accounts. Which solution meets these requirements?
Answer and explanation
Answer: D. Consolidated billing aggregates usage so volume tiers apply across the organization, and Savings Plans and Reserved Instance benefits are shared among member accounts. Budgets track and alert on spend without aggregating pricing tiers. Collapsing 40 accounts into one destroys the isolation multi-account design provides. Per-account purchases forgo the sharing entirely.
182. An organization runs a steady mix of Amazon EC2, AWS Fargate, and AWS Lambda workloads, and frequently changes EC2 instance families as applications evolve. Which purchasing option meets these requirements?
Answer and explanation
Answer: B. Compute Savings Plans apply across EC2 instance families and Regions and also cover Fargate and Lambda, so the discount follows a changing mix. Standard Reserved Instances lock to a family and would strand the commitment. Convertible Reserved Instances allow exchange but cover EC2 only. Spot is unsuitable for steady production that cannot absorb interruption.
183. Development Amazon RDS and Amazon EC2 resources run continuously but are used only during weekday business hours. Which solution meets these requirements?
Answer and explanation
Answer: D. Stopped EC2 and RDS instances incur no instance-hour charges, so scheduling removes roughly two-thirds of the cost, and a budget alert catches drift. Reserved Instances commit to continuous usage the workload does not have. Downgrading still pays for idle hours. Delete and recreate is slow, risky, and loses configuration.
184. A batch workload runs on AWS Fargate for four hours each night and tolerates interruption. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: D. Fargate Spot offers a substantial discount for interruption-tolerant tasks, which matches this workload exactly. A larger task size raises the hourly rate. A Savings Plan covering the full day commits to capacity used only four hours. On-Demand EC2 adds instance management without a discount.
185. A company must obtain right-sizing recommendations for Amazon EC2, Amazon EBS, AWS Lambda, and Amazon ECS resources based on observed utilization. Which solution meets these requirements?
Answer and explanation
Answer: A. Compute Optimizer analyses utilization history and recommends specific configurations with projected performance and cost impact. Cost Explorer reports spend without recommending configurations. Budgets alert on thresholds. Dashboards visualise metrics without generating recommendations.
186. A steady production workload will run for at least three years, and the company wants the largest available discount against On-Demand pricing. Which purchasing option should be evaluated first?
Answer and explanation
Answer: D. Steady, predictable, long-running usage is what commitment-based pricing rewards, and a three-year term yields the deepest discount. A one-year term discounts less than a three-year term for a workload known to run that long. Spot offers a larger raw discount but instances can be reclaimed, which is unsuitable for steady production unless the workload tolerates interruption. Dedicated Hosts address licensing and isolation needs and cost more.
187. A reporting database on Amazon RDS is queried only during a four-hour window each weekday, but the instance runs continuously. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: A. A stopped RDS instance incurs no instance-hour charges, so scheduling removes roughly four fifths of the cost for a workload used twenty hours a week. A Reserved Instance commits to continuous usage the workload does not have. A burstable class still pays for every idle hour and can throttle during the reporting window. Storage auto scaling manages capacity rather than instance hours.
188. A DynamoDB table serves an application whose traffic is steady and well understood, and the team wants to reduce cost below on-demand pricing. Which solution meets these requirements?
Answer and explanation
Answer: A. Provisioned capacity with auto scaling costs less than on-demand for predictable traffic, and reserved capacity discounts the steady baseline further. Provisioning for the peak pays for headroom that is rarely used. An index adds write cost rather than reducing spend. DAX reduces read latency and adds cluster cost.
189. An Amazon Aurora cluster supports a development workload that is idle most of the day and busy for short unpredictable periods. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: D. Aurora Serverless v2 scales capacity in fine increments and costs far less during long idle periods than a provisioned cluster. Provisioning for the peak pays continuously. Sizing for the average fails during busy periods and replicas add cost. A Reserved Instance commits to continuous usage that an idle development workload does not have.
190. A relational database stores seven years of transaction history, but queries almost never touch data older than one year. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: D. Moving cold history to S3 in a columnar format removes it from expensive database storage while keeping it queryable through Athena at a fraction of the cost. More storage and replicas increase spend. Deleting data older than a year violates the seven-year retention. Migrating to DynamoDB changes the data model without addressing the cost of retaining cold data.
191. An application repeatedly issues the same expensive query against Amazon RDS, and the database instance has been scaled up twice to cope. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: C. Caching removes the repeated work entirely, which allows the instance to be scaled back down and is cheaper than adding database capacity. Read replicas add instances that each cost money to serve work a cache would eliminate. Converting to Aurora changes the engine without removing the repeated query. More IOPS addresses storage throughput rather than repeated identical work.
192. A team must reduce the cost of storing infrequently accessed backups of an Amazon RDS database while keeping them restorable. Which solution meets these requirements?
Answer and explanation
Answer: A. Exporting snapshots to S3 allows lifecycle transitions to colder classes, which costs far less than retaining many snapshots at standard rates. Reducing retention to one day weakens recovery. Longer retention increases stored volume and cost. Copying to another Region adds cost rather than reducing it.
193. Data transfer costs are high because Amazon EC2 instances in private subnets retrieve large objects from Amazon S3 through a NAT gateway. Which solution meets these requirements?
Answer and explanation
Answer: C. A gateway endpoint costs nothing and removes both the NAT data processing charge and the traffic itself from the NAT path. Moving instances to public subnets trades a cost problem for a security exposure. A NAT instance shifts cost to an instance the team must operate and scales poorly. Transfer Acceleration adds a premium and would increase cost.
194. The largest cost line in an account is data transfer out to the internet from Amazon EC2 instances serving media files. Which solution meets these requirements?
Answer and explanation
Answer: D. CloudFront both reduces the per-gigabyte transfer price relative to direct EC2 egress and serves repeat requests from cache, cutting origin transfer as well. A cheaper Region changes compute price rather than egress volume. A larger instance transfers the same bytes. Snapshots add storage cost and do not affect egress.
195. A company must be alerted to unexpected increases in AWS spend as they occur rather than at the end of the month. Which solution meets these requirements?
Answer and explanation
Answer: B. Cost Anomaly Detection learns spending patterns and alerts on statistically unusual increases without a threshold being defined in advance. A fixed budget threshold catches only totals crossing a preset line and misses an unusual increase within budget. Monthly Cost Explorer review is retrospective. Trusted Advisor identifies savings opportunities rather than alerting on anomalies.
196. A company must attribute AWS spend to individual teams and projects within a single account. Which solution meets these requirements?
Answer and explanation
Answer: C. Cost allocation tags applied to resources and activated for billing let costs be grouped by team or project in Cost Explorer and the billing reports. Budgets track thresholds rather than attributing spend. CloudTrail records API activity rather than resource cost. Separating teams by Region distorts architecture for a reporting need and adds latency and complexity.
197. Instances in three Availability Zones route outbound traffic through a single NAT gateway in one Availability Zone, and cross-zone data processing charges are significant. Which solution meets these requirements?
Answer and explanation
Answer: C. A NAT gateway per Availability Zone keeps outbound traffic within its own zone, removing cross-zone data transfer charges and also removing a single point of failure. A second gateway in the same zone does not change the cross-zone path. A NAT instance shifts cost to a managed instance and scales poorly. Consolidating into one zone removes the resilience the multi-zone design provides.
198. A workload transfers large volumes between two VPCs in the same Region, and inter-VPC data transfer cost must be reduced. Which solution meets these requirements?
Answer and explanation
Answer: C. VPC peering within a Region carries lower data transfer charges than routing through a NAT gateway or over public addresses, and adds no hourly attachment fee. NAT gateways add both an hourly charge and data processing charges. Routing over public addresses incurs internet data transfer rates. Transit Gateway adds per-attachment and per-gigabyte charges that peering avoids for a simple two-VPC case.
199. An application's Amazon CloudFront distribution serves users in a small number of countries, and the team wants to reduce delivery cost. Which solution meets these requirements?
Answer and explanation
Answer: D. CloudFront price classes limit delivery to a subset of edge locations at a lower per-gigabyte rate, which suits an audience concentrated in a few countries. The all-locations price class is the most expensive. Disabling caching increases origin requests and cost. A shorter TTL increases origin fetches for the same reason.
200. Objects must be moved to a lower-cost storage class after 30 days and archived after 90 days. Which solution meets these requirements?
Answer and explanation
Answer: B. Lifecycle transitions apply automatically at defined ages, which suits a known access pattern. Manual movement is unreliable. Intelligent-Tiering suits unpredictable access and adds a monitoring charge. A copying function recreates a built-in capability.
201. Incomplete multipart uploads are accumulating in an S3 bucket and incurring storage cost. Which solution meets these requirements?
Answer and explanation
Answer: C. A lifecycle rule aborting incomplete uploads removes the accumulated parts automatically. Versioning increases stored objects. Transfer Acceleration speeds uploads. Deleting the bucket loses the data.
202. Amazon EBS snapshots are accumulating and must be retained according to a defined schedule. Which solution meets these requirements?
Answer and explanation
Answer: A. Data Lifecycle Manager creates and expires snapshots on a defined schedule. Manual deletion is unreliable. Encryption is unrelated to retention. Volume size does not affect snapshot count.
203. A workload runs continuously for three years on a consistent instance family. Which purchasing option minimizes cost?
Answer and explanation
Answer: D. A three-year commitment on a consistent family gives the deepest discount. On-Demand forgoes it. Spot is unsuitable for a workload requiring continuous availability. A one-year Convertible commitment gives a smaller discount.
204. An organization must identify EC2 instances that are consistently underutilized. Which solution meets these requirements?
Answer and explanation
Answer: D. Compute Optimizer analyses utilization and recommends specific sizes. The bill shows cost rather than utilization. Configuration shows what was provisioned. Blind reduction risks outages.
205. A development environment is used only during business hours. Which solution reduces cost?
Answer and explanation
Answer: A. Stopping outside business hours removes the cost of idle time. Smaller instances still run continuously. Reserved Instances commit to continuous usage. A cheaper Region reduces the rate while still paying for idle hours.
206. A database workload is active a few hours each day with long idle periods. Which solution minimizes cost?
Answer and explanation
Answer: C. Aurora Serverless v2 scales down during idle periods. A provisioned cluster and RDS instances run continuously. A Reserved Instance commits to continuous usage.
207. A DynamoDB table's traffic is highly variable and difficult to forecast. Which capacity mode minimizes cost while avoiding throttling?
Answer and explanation
Answer: B. On-demand mode charges per request and absorbs variability without planning. Peak provisioning pays for idle capacity. Average provisioning throttles at peak. Reserved capacity commits to a provisioned baseline.
208. An Amazon RDS database's automated backups are retained longer than the business requires. Which action reduces cost?
Answer and explanation
Answer: C. Reducing retention to the requirement lowers backup storage cost while preserving recovery. Disabling backups removes recovery capability. Instance size and Multi-AZ increase cost.
209. An application's data transfer cost is dominated by traffic from EC2 instances to the internet. Which solution reduces cost?
Answer and explanation
Answer: D. CloudFront reduces egress pricing and serves repeat requests from cache. Zone placement affects inter-zone transfer rather than internet egress. Instance size and enhanced networking affect performance rather than transfer pricing.
210. Instances in private subnets across three Availability Zones share a single NAT gateway, and cross-zone data charges are significant. Which solution reduces cost?
Answer and explanation
Answer: B. A NAT gateway per zone removes cross-zone data charges and also removes the single point of failure. A second gateway in the same zone does neither. A NAT instance shifts cost and reduces availability. Consolidating to one zone sacrifices availability.
211. An application in a VPC makes frequent calls to Amazon DynamoDB through a NAT gateway. Which solution reduces cost?
Answer and explanation
Answer: A. A gateway endpoint for DynamoDB is free and removes the NAT data processing charge. NAT gateways do not have a size setting. A public subnet trades cost for exposure. DAX caches reads rather than changing the network path.
212. Objects must be retained for compliance but are never expected to be read. Which solution meets these requirements?
Answer and explanation
Answer: D. Deep Archive is the lowest-cost class for data that is effectively never read. Standard-Infrequent Access and Standard both cost more, and Intelligent-Tiering adds a monitoring charge for a pattern already known.
213. An S3 bucket's storage cost must be reduced without changing how objects are accessed. Which solution meets these requirements?
Answer and explanation
Answer: B. Intelligent-Tiering reduces cost without changing access behaviour. Deep Archive imposes retrieval delay, deletion loses data, and versioning increases stored objects.
214. An EBS volume's cost must be reduced for a workload that does not need provisioned IOPS. Which solution meets these requirements?
Answer and explanation
Answer: B. gp3 provides configurable baseline performance at lower cost than provisioned IOPS types. io2 costs more, larger volumes cost more, and snapshots add cost.
215. Snapshots are accumulating and must be retained according to a defined schedule at the lowest cost. Which solution meets these requirements?
Answer and explanation
Answer: D. A lifecycle policy with an archive tier retains what is required at the lowest cost. Indefinite retention grows without bound, a one-week rule may violate requirements, and cross-Region copies add cost.
216. An EFS file system's cost must be reduced for files that are rarely accessed. Which solution meets these requirements?
Answer and explanation
Answer: B. EFS lifecycle management transitions cold files automatically. Deletion loses data, throughput cannot be zero, and Region changes do not reduce storage cost.
217. Objects must be available for immediate retrieval but are accessed only a few times a year. Which solution meets these requirements?
Answer and explanation
Answer: B. Glacier Instant Retrieval gives millisecond access at archive pricing. Flexible Retrieval requires a restore, Standard costs more, and One Zone reduces durability.
218. Data that can be regenerated must be stored at the lowest cost with reduced durability accepted. Which solution meets these requirements?
Answer and explanation
Answer: D. One Zone-IA reduces cost by storing in one zone, which suits regenerable data. Standard-IA and Standard store across zones at higher cost, and Deep Archive imposes retrieval delay.
219. An organization must identify which S3 prefixes are driving storage cost. Which solution meets these requirements?
Answer and explanation
Answer: C. Storage Lens reports usage and activity by prefix. The invoice aggregates, listing every object does not scale, and access logging records requests.
220. Incomplete multipart uploads must be prevented from accumulating cost. Which solution meets these requirements?
Answer and explanation
Answer: A. A lifecycle rule aborts incomplete uploads automatically. Versioning adds objects, part size does not prevent abandonment, and deleting the bucket loses data.
221. Objects in a bucket must transition through several storage classes as they age. Which solution meets these requirements?
Answer and explanation
Answer: A. One lifecycle configuration expresses every transition. Manual movement is unreliable, per-class buckets fragment the data, and a copying function duplicates objects.
222. An organization must reduce the cost of storing many small objects in Amazon S3. Which solution meets these requirements?
Answer and explanation
Answer: A. Combining small objects reduces per-object overhead and avoids minimum billable size penalties in colder classes. Archiving them individually can cost more, versioning adds objects, and request rate is unrelated.
223. A backup strategy must retain daily backups for a month and monthly backups for a year at the lowest cost. Which solution meets these requirements?
Answer and explanation
Answer: C. Separate rules with cold storage for older points meets both requirements economically. Uniform year-long retention costs more, a single backup fails the requirement, and cross-Region copies add cost.
224. An organization must reduce the cost of EBS snapshots retained for years. Which solution meets these requirements?
Answer and explanation
Answer: A. The archive tier reduces long-term snapshot cost. Deleting loses the backups, manual copying is not supported in that form, and volume size does not change existing snapshots.
225. A data lake's cost must be reduced by storing data in a more efficient format. Which solution meets these requirements?
Answer and explanation
Answer: A. Compressed columnar formats reduce both storage and the bytes scanned per query. CSV and JSON are row-oriented and larger, and partition count affects pruning rather than size.
226. An organization must avoid paying for S3 requests generated by an inefficient access pattern. Which solution meets these requirements?
Answer and explanation
Answer: D. Batching and caching reduce request volume. Colder classes increase per-request cost, request limits govern throttling, and transfer acceleration adds cost.
227. A solution must estimate the storage cost of a planned architecture before it is built. Which solution meets these requirements?
Answer and explanation
Answer: A. The Pricing Calculator estimates from expected volumes and patterns. Deploying to find out is after the fact, a previous project differs, and assuming negligibility is how storage cost surprises arise.
228. An organization must reduce cost for a bucket where objects are written once and read within the first week. Which solution meets these requirements?
Answer and explanation
Answer: B. A transition after the known active period matches cost to the pattern. Indefinite Standard storage pays frequent-access rates, deletion may violate retention, and Intelligent-Tiering adds monitoring cost for a known pattern.
229. An organization must control the cost of cross-Region replication. Which solution meets these requirements?
Answer and explanation
Answer: D. A replication filter limits what is copied to what needs copying. Full replication, manual copies, and additional Regions all increase cost or effort.
230. A solution must reduce the cost of retrieving archived objects that are occasionally needed urgently. Which solution meets these requirements?
Answer and explanation
Answer: B. Selecting the retrieval tier per request balances urgency against cost. Always expedited is expensive, always bulk fails urgent requests, and leaving the archive class raises storage cost.
231. An organization must identify objects that have not been accessed and could be archived. Which solution meets these requirements?
Answer and explanation
Answer: D. Access analysis identifies genuinely unused objects. Age is a poor proxy, deleting without confirmation risks loss, and archiving everything penalises active data.
232. A workload runs a predictable eight hours each weekday. Which solution meets these requirements?
Answer and explanation
Answer: C. Stopping outside the schedule removes the idle charge. Reserved Instances commit to continuous usage, smaller instances still run, and Spot suits interruption-tolerant work rather than a fixed schedule.
233. A workload's instance family will change within the year as the application is refactored. Which solution meets these requirements?
Answer and explanation
Answer: B. A Compute Savings Plan follows changes in family and Region. Standard Reserved Instances lock to a family, Convertible exchange is possible but gives a smaller discount, and On-Demand forgoes the saving.
234. A batch workload can be interrupted and restarted. Which solution meets these requirements?
Answer and explanation
Answer: C. Spot with checkpointing gives the deepest discount for interruption-tolerant work. On-Demand is the baseline, Reserved Instances commit to continuous usage, and Dedicated Hosts carry a premium.
235. A Lambda function's cost must be reduced for a workload that is CPU bound. Which solution meets these requirements?
Answer and explanation
Answer: D. More memory allocates more CPU, and the shorter duration can reduce total cost for CPU-bound work. Less memory slows it, and timeout and concurrency do not change per-invocation cost.
236. An organization must identify EC2 instances that are consistently over-provisioned. Which solution meets these requirements?
Answer and explanation
Answer: B. Compute Optimizer recommends sizes from observed utilization. Inventory shows what is provisioned, blind reduction risks outages, and service-level billing does not identify instances.
237. A containerized workload's cost must be reduced without managing instances. Which solution meets these requirements?
Answer and explanation
Answer: D. Fargate Spot reduces cost for interruption-tolerant containers with no instances to manage. Fargate On-Demand is the baseline, and EC2 and Dedicated Hosts reintroduce instance management.
238. An organization must commit to a discount without committing to a specific instance family or Region. Which solution meets these requirements?
Answer and explanation
Answer: B. A Compute Savings Plan is the most flexible commitment. An EC2 Instance Savings Plan commits to a family in a Region, Standard Reserved Instances commit further, and Capacity Reservations reserve capacity without a discount commitment.
239. A database workload runs continuously with a stable instance class for three years. Which solution meets these requirements?
Answer and explanation
Answer: B. A three-year commitment gives the deepest discount for stable continuous usage. On-Demand forgoes it, serverless suits intermittent workloads, and annual renewal gives a smaller discount.
240. A DynamoDB table's traffic is steady and well understood. Which solution meets these requirements?
Answer and explanation
Answer: D. Provisioned capacity with auto scaling suits predictable traffic, and reserved capacity discounts the baseline. On-demand costs more for steady traffic, peak provisioning wastes capacity, and minimum provisioning throttles.
241. An RDS database's storage cost must be reduced where the allocated storage far exceeds what is used. Which solution meets these requirements?
Answer and explanation
Answer: A. Right-sizing allocated storage reduces cost. Increasing it raises cost, autoscaling with a high maximum does not reduce current allocation, and snapshots add cost.
242. A database's read replicas are underused outside business hours. Which solution meets these requirements?
Answer and explanation
Answer: A. Removing unneeded replicas removes their charge. Larger replicas cost more, Multi-AZ standbys are for availability, and continuous retention is the cost being addressed.
243. An Aurora cluster's cost must be reduced for a development environment used intermittently. Which solution meets these requirements?
Answer and explanation
Answer: D. Serverless v2 scales down during idle periods automatically. Provisioned clusters run continuously, replicas add cost, and manual stopping depends on someone remembering.
244. A database's backup storage cost must be reduced without losing required recovery capability. Which solution meets these requirements?
Answer and explanation
Answer: A. Matching retention to the requirement and removing unneeded manual snapshots reduces backup storage. Disabling backups removes recovery, longer retention costs more, and cross-Region copies add cost.
245. An application transfers large volumes between instances in different Availability Zones. Which solution meets these requirements?
Answer and explanation
Answer: D. Cross-zone transfer is charged, so co-location reduces it where availability allows. Different Regions cost more, Elastic IP addresses can increase charges by routing over public addresses, and bandwidth does not change per-gigabyte pricing.
246. Instances communicate using public IP addresses although they are in the same VPC. Which solution meets these requirements?
Answer and explanation
Answer: B. Private addressing keeps traffic within the VPC at no public transfer charge. Elastic IP addresses, NAT gateways, and load balancers all add cost or public routing.
247. An application in a VPC makes heavy use of Amazon S3 through a NAT gateway. Which solution meets these requirements?
Answer and explanation
Answer: C. A gateway endpoint for S3 is free and removes the NAT data processing charge. NAT gateways scale automatically, a public subnet trades cost for exposure, and an interface endpoint bills hourly.
248. A content delivery solution must reduce the cost of serving large files to global users. Which solution meets these requirements?
Answer and explanation
Answer: C. CloudFront reduces egress pricing and serves repeat requests from cache. Direct origin serving pays higher egress, per-Region replication multiplies storage, and compression reduces bytes without changing the rate.
249. Data must be transferred into AWS from an on-premises data center. Which solution meets these requirements?
Answer and explanation
Answer: C. Inbound transfer from the internet is generally free, so the concern is bandwidth and time rather than charge. Snowball suits cases where bandwidth is inadequate, and compression and scheduling address duration rather than cost.
250. An organization must reduce the number of NAT gateways without losing availability. Which solution meets these requirements?
Answer and explanation
Answer: B. One gateway per zone balances availability against cost and avoids cross-zone charges. A single gateway is a single point of failure, per-subnet gateways multiply cost, and NAT instances reduce availability.
251. Traffic between VPCs in the same Region must be carried at the lowest cost. Which solution meets these requirements?
Answer and explanation
Answer: C. Peering carries no hourly attachment charge, though data transfer still applies. Transit gateway attachments bill hourly, VPNs add cost and overhead, and NAT gateways route to the internet.
252. An application's data transfer cost is driven by responses to internet users. Which solution meets these requirements?
Answer and explanation
Answer: C. Fewer bytes transferred reduces egress cost directly. Instance size, Region, and zone count do not change the volume sent to users.
253. A solution must estimate data transfer cost for a planned multi-Region design. Which solution meets these requirements?
Answer and explanation
Answer: C. Modelling each boundary before building avoids a surprise. Assuming it is small is the common error, compute cost is unrelated, and measuring afterwards is too late to influence the design.
254. An organization must reduce the cost of a Direct Connect connection used intermittently. Which solution meets these requirements?
Answer and explanation
Answer: D. Port hours are charged regardless of traffic, so right-sizing the connection reduces cost. A faster port and a second connection both cost more, and keeping an unused port pays for it.
255. An application's CloudFront costs must be reduced where most viewers are in a few Regions. Which solution meets these requirements?
Answer and explanation
Answer: B. A price class limits which edge locations serve traffic, reducing cost where viewers are concentrated. Disabling caching and shortening time to live both increase origin requests, and more origins do not reduce cost.
256. A workload's objects are written once and read many times over several years, with access declining sharply after the first month. Which solution meets these requirements at the lowest cost?
Answer and explanation
Answer: C. A transition after the known active period matches cost to the access pattern. Standard pays frequent-access rates throughout, immediate deep archiving imposes retrieval delay during the active month, and Intelligent-Tiering adds monitoring cost for a pattern already understood.