SAA-C03 Design High-Performing Architectures Practice Test 3 — 15 Questions

Question 1

Based on the exhibit, the team wants to improve application performance without changing the code. Which EC2 instance family should they choose next?

Accepted Answer

Choose a memory-optimized instance family such as R6i to provide more RAM.. The exhibit shows a memory-constrained application (e.g., high cache miss rates or swap usage) where performance is bottlenecked by insufficient RAM. Choosing a memory-optimized instance family like R6i provides more RAM per vCPU, allowing the application to keep more data in memory and reduce disk I/O, directly improving performance without code changes.

Answer

Choose a compute-optimized instance family such as C6i to increase CPU performance.

Answer

Choose a storage-optimized instance family such as I4i to improve block storage throughput.

Answer

Choose a burstable instance family such as T3 to reduce cost and improve performance.

Question 2

Based on the exhibit, what change best reduces Lambda cold-start impact for a predictable user-upload workflow?

Accepted Answer

Enable provisioned concurrency for the function.. Provisioned concurrency initializes a specified number of execution environments in advance, so when a user upload triggers the Lambda function, there is no cold-start delay. This directly addresses the predictable, user-upload workflow by ensuring warm containers are ready to handle requests immediately.

Answer

Set a reserved concurrency limit for the function to protect it from throttling.

Answer

Increase the function timeout to give more time for initialization.

Answer

Move the function to a larger memory setting only to eliminate all initialization time.

Question 3

A team runs a latency-sensitive service on EC2 and needs consistent, low-latency block storage for a database. The application requires predictable performance and should be fast for random reads/writes. Which EBS volume type is the best choice?

Accepted Answer

EBS gp3 (general purpose SSD). B is correct because gp3 is a general-purpose SSD that provides consistent, low-latency performance for random read/write operations, making it ideal for latency-sensitive databases. It offers a baseline of 3,000 IOPS and 125 MB/s throughput, with the ability to independently scale IOPS up to 16,000 and throughput up to 1,000 MB/s, ensuring predictable performance without the burst-bucket limitations of gp2.

Answer

EBS st1 (throughput optimized HDD)

Answer

EBS sc1 (cold HDD)

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EBS magnetic (legacy magnetic)

Question 4

A new feature stores user events in DynamoDB. Each event must be fetched by user_id and sorted by event_time. The team expects many different users and wants to avoid a single hot partition. Which partition key design is best?

Accepted Answer

Use user_id as the partition key and event_time as the sort key.. Option B is correct because using user_id as the partition key evenly distributes writes across partitions, avoiding hot spots, while event_time as the sort key enables efficient retrieval of events for a specific user in chronological order. DynamoDB's query operation can then fetch all events for a given user_id sorted by event_time without scanning.

Answer

Use a constant partition key value (for example, partition_key='events') and store user_id as an attribute.

Answer

Use event_time as the partition key and user_id as an attribute to query later.

Answer

Use a randomly generated UUID as the partition key and query by user_id using a full table scan.

Question 5

Based on the exhibit, which AWS feature should the team use to minimize network latency between EC2 instances that exchange messages very frequently?

Accepted Answer

Use a cluster placement group to place instances close together.. A cluster placement group is the correct choice because it places EC2 instances in a low-latency, high-bandwidth network within a single Availability Zone. This minimizes network latency between instances that exchange messages very frequently, as the instances are physically close together and can communicate using up to 10 Gbps of network throughput for most instance types.

Answer

Use a spread placement group to maximize instance separation across hardware.

Answer

Use a partition placement group to distribute instances across many partitions.

Answer

Use multiple Auto Scaling groups to spread traffic across more subnets.

Question 6

A web service runs on an Auto Scaling group (ASG). The team updates configuration (AMIs, environment variables) in a Launch Template and wants new instances created during scale-out to use the latest Launch Template version. What should the architect do?

Accepted Answer

Set the ASG to use the latest Launch Template version and optionally start an instance refresh for existing instances.. Option B is correct because the ASG can be configured to use the latest version of a Launch Template by specifying the `$Latest` version alias. This ensures that any new instances launched during scale-out automatically use the most recent template configuration (e.g., updated AMI, environment variables). Additionally, an Instance Refresh can be triggered to roll the update across existing instances, aligning them with the same latest template version without manual intervention.

Answer

Leave the ASG attached to the previous Launch Template version so scale-out is stable.

Answer

Manually SSH into each new instance and reconfigure it after it launches.

Answer

Move the configuration changes into a security group rule so the ASG updates them automatically.

Question 7

A team runs a stateless web app on Amazon EC2 behind an Application Load Balancer. During traffic spikes, new EC2 instances take several minutes to finish bootstrapping before they can receive traffic. Which Auto Scaling configuration most directly reduces the time until additional capacity is available?

Accepted Answer

Use an Auto Scaling warm pool so pre-initialized instances are ready to enter service.. Option B is correct because an Auto Scaling warm pool allows you to maintain a pool of pre-initialized instances that are ready to quickly enter the target group and start serving traffic. Instead of waiting for new instances to boot and configure during a scale-out event, the warm pool provides instances that have already completed bootstrapping, drastically reducing the time to additional capacity.

Answer

Increase the ALB target group deregistration delay.

Answer

Reduce the Auto Scaling group minimum size to one instance.

Answer

Replace the Application Load Balancer with a Network Load Balancer.

Question 8

A company runs a stateless application tier behind an Application Load Balancer. Match each observed scaling pattern on the left to the best Auto Scaling strategy or metric on the right.

Question 9

A compute workload uses temporary scratch space for intermediate results (reproducible), and it can tolerate data loss if the instance is terminated. The workload benefits from very high local I/O throughput. Which storage option is the best fit for the scratch data?

Accepted Answer

Instance store for local temporary files that can be lost when the instance stops.. Instance store volumes provide very high local I/O throughput because they are physically attached to the host server, making them ideal for temporary scratch data that is reproducible and can tolerate loss. Since the workload explicitly accepts data loss on instance termination and does not require persistence across reboots, instance store is the best fit for this use case.

Answer

Amazon EBS General Purpose (gp3) volumes to persist intermediate results across reboots.

Answer

Amazon EFS for a shared file system between multiple instances.

Answer

Amazon S3 for scratch data so it is always durable and accessible from anywhere.

Question 10

Based on the exhibit, which change best reduces latency during peak traffic without overprovisioning the fleet?

Accepted Answer

Change the Auto Scaling policy to target tracking on ALB RequestCountPerTarget.. Option B is correct because using a target tracking scaling policy on ALB RequestCountPerTarget dynamically adjusts the fleet size based on the actual number of requests each instance receives. This ensures that during peak traffic, additional instances are added only when needed, reducing latency by distributing the load without overprovisioning. It directly addresses the goal of minimizing latency during spikes while maintaining cost efficiency.

Answer

Replace the instances with a larger instance family so each server has more headroom.

Answer

Use scheduled scaling to add instances only during the business hours peak window.

Answer

Replace the ALB with a Network Load Balancer to reduce request latency.

Question 11

A retail analytics app uses Amazon RDS for PostgreSQL. Read traffic is growing, and the database CPU spikes mainly due to SELECT-heavy workloads. Writes are less frequent, and the app can tolerate eventually consistent reads for the reports. What is the most appropriate AWS-native way to improve read performance with minimal application changes?

Accepted Answer

Create an RDS read replica and point the reporting queries to the replica endpoint.. Creating an RDS read replica is the most appropriate AWS-native solution because it offloads SELECT-heavy workloads from the primary database instance to a read-only copy, reducing CPU spikes on the primary. The application can tolerate eventually consistent reads for reports, which is exactly the consistency model of RDS read replicas (typically sub-second replication lag). This requires minimal application changes—only updating the reporting queries to point to the replica endpoint—and fully leverages PostgreSQL's built-in replication capabilities.

Answer

Switch the cluster to DynamoDB without redesigning the data model.

Answer

Enable S3 event notifications to trigger a Lambda function after each write to the database.

Answer

Replace the RDS instance class with a smaller size to reduce cost and improve performance.

Question 12

A media company uses CloudFront in front of an S3 bucket origin for video thumbnails. They want to prevent users from bypassing CloudFront and accessing the S3 bucket directly, while still allowing CloudFront to fetch objects. What is the best option?

Accepted Answer

Use CloudFront Origin Access Control (OAC) or Origin Access Identity (OAI) and update the bucket policy to allow only CloudFront.. CloudFront Origin Access Control (OAC) or Origin Access Identity (OAI) allows you to restrict direct access to an S3 bucket by configuring the bucket policy to grant read permissions only to the CloudFront distribution's service principal. This ensures that users can only retrieve thumbnails through CloudFront, leveraging its caching and security features, while blocking any direct S3 requests.

Answer

Keep the bucket public and rely on signed cookies for all thumbnail requests.

Answer

Enable S3 static website hosting so users access thumbnails directly from the S3 website endpoint.

Answer

Set S3 bucket permissions to allow all IAM users and block access only by using a WAF rule at CloudFront.

Question 13

Based on the exhibit, which change will most improve the CloudFront cache hit ratio for the static assets while still serving the same files to all users?

Accepted Answer

Create a custom cache policy that includes only the v query string and excludes cookies.. Option A is correct because static assets (e.g., images, CSS, JS) are typically served identically to all users, so forwarding a unique query string like 'v' for versioning still allows CloudFront to cache a single object per version. By excluding cookies and other query strings, you prevent cache fragmentation caused by irrelevant variations, directly improving the cache hit ratio. This custom cache policy ensures that requests for the same 'v' value are served from the edge cache rather than forwarded to the origin.

Answer

Enable Origin Shield and keep the current cache behavior unchanged.

Answer

Move the static assets to individual presigned URLs for each viewer.

Answer

Increase the CloudFront default TTL to 24 hours while continuing to forward all cookies and query strings.

Question 14

Based on the exhibit, what is the best change to improve read performance without increasing write latency on the primary database?

Accepted Answer

Create an RDS read replica and direct the reporting queries to the replica endpoint.. Creating an RDS read replica offloads read-heavy reporting queries from the primary database instance, improving read performance without increasing write latency on the primary. The replica operates asynchronously, so writes on the primary are not blocked or delayed by the reporting workload.

Answer

Convert the DB instance to Multi-AZ so the primary can serve more reads.

Answer

Increase the primary instance class to a larger size and keep all traffic on one writer.

Answer

Migrate the reporting workload to DynamoDB to gain faster reads.

Question 15

Based on the exhibit, which storage design best supports the application servers' shared working directory requirement?

Accepted Answer

Mount Amazon EFS on every EC2 instance and use it as the shared workspace.. Amazon EFS provides a fully managed, NFS-based shared file system that can be mounted concurrently on multiple EC2 instances across multiple Availability Zones. This directly satisfies the requirement for a shared working directory where all application servers can read and write files simultaneously without additional synchronization overhead.

Answer

Attach one gp3 EBS volume to each instance and synchronize the files with cron jobs.

Answer

Store the artifacts in S3 and have each node read them directly from S3 as a filesystem.

Answer

Use instance store on each instance because it provides the fastest local file access.

SAA-C03 Design High-Performing Architectures Practice Test 3 — 15 Questions

Exhibit

SAA-C03 Design High-Performing Architectures Practice Test 3 — 15 Questions

Exhibit