SAA-C03 Design High-Performing Architectures Practice Test 5 — 15 Questions

Question 1

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 fully bootstrapped and ready to enter service. When a scale-out event occurs, instances from the warm pool can be moved into the Auto Scaling group and start receiving traffic almost immediately, bypassing the several-minute bootstrapping delay.

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 2

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 logic.

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.

Question 3

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. Since the workload can tolerate data loss and the scratch data is reproducible, the ephemeral nature of instance store is acceptable, and it offers the best performance for temporary, high-throughput scratch space.

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 4

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.. Option B is correct because CloudFront Origin Access Control (OAC) or Origin Access Identity (OAI) allows you to create a special CloudFront identity and attach a bucket policy that grants that identity s3:GetObject permissions. This ensures that only CloudFront can fetch objects from the S3 bucket, while direct access via the S3 endpoint is denied, preventing users from bypassing CloudFront.

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 5

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 pre-warms a specified number of execution environments so that when a user upload triggers the Lambda function, there is no cold-start latency. This is the most direct way to eliminate initialization time for a predictable workload, as it keeps instances 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 6

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 that the application is experiencing high memory utilization (e.g., memory pressure or swapping), which degrades performance. Choosing a memory-optimized instance family such as R6i provides more RAM per vCPU, directly addressing the bottleneck without requiring code changes. This improves application performance by reducing or eliminating swap usage and allowing more data to be cached in memory.

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 7

A system uses multiple AWS Lambda functions behind different event sources. One Lambda occasionally spikes and causes other Lambdas to be throttled due to shared concurrency limits. Which setting best helps ensure the important Lambda keeps capacity during spikes?

Accepted Answer

Set Reserved Concurrency for the important Lambda function.. Reserved Concurrency guarantees that the important Lambda function always has a set number of concurrent executions available, preventing other functions from consuming the account-level concurrency pool and throttling it during spikes. This setting isolates the function's capacity from shared contention, ensuring its performance remains stable.

Answer

Increase the function timeout so throttling is less likely.

Answer

Enable Provisioned Concurrency for every Lambda in the account.

Answer

Reduce the number of IAM policies attached to the Lambda roles.

Question 8

Based on the exhibit, which Amazon EFS performance mode is the best fit for this workload?

Accepted Answer

Use General Purpose performance mode for low-latency access.. General Purpose performance mode is the best fit for this workload because it provides the lowest latency for file operations, which is critical for applications like content management, web serving, or home directories that require consistent, sub-millisecond metadata latency. Max I/O mode, in contrast, trades off latency for higher throughput and IOPS, making it unsuitable for latency-sensitive workloads.

Answer

Use Max I/O performance mode to optimize for the highest possible latency tolerance.

Answer

Use One Zone storage class to increase metadata speed.

Answer

Use Provisioned Throughput mode because it is the only performance mode available.

Question 9

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 Auto Scaling group can be configured to use the latest version of a launch template by specifying the `$Latest` version. This ensures that any new instances launched during scale-out automatically use the most recent configuration. Additionally, an instance refresh can be initiated to update existing instances to the 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 10

Your application uses ElastiCache Redis as a cache for user profiles stored in DynamoDB. You must ensure that when a profile is updated, subsequent reads see the latest value quickly. Which cache strategy is generally the best fit for this requirement?

Accepted Answer

Use a cache-aside approach with TTL plus explicit invalidation after writes.. Option B is correct because a cache-aside (lazy loading) strategy with TTL and explicit invalidation ensures that after a write to DynamoDB, the stale Redis entry is removed, forcing the next read to fetch the fresh profile from DynamoDB and repopulate the cache. This combination minimizes the window of stale reads while maintaining high read performance, which is critical for user profile caches where consistency matters.

Answer

Write to DynamoDB only, and never update or invalidate the Redis cache.

Answer

Cache only for reads, and do not fetch from DynamoDB when a key is missing.

Answer

Rely on eventual consistency of Redis replication to propagate updates to all nodes.

Question 11

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 groups EC2 instances within a single Availability Zone with low-latency, high-bandwidth networking, achieving single-digit millisecond latency between instances. This is ideal for applications that exchange messages very frequently, as it minimizes network hops and maximizes throughput.

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 12

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 volume that provides consistent, low-latency performance for random read/write operations, making it ideal for latency-sensitive database workloads. It offers a baseline of 3,000 IOPS and 125 MB/s throughput, with the ability to independently scale up to 16,000 IOPS and 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)

Answer

EBS magnetic (legacy magnetic)

Question 13

A customer-facing application has a relational data model and needs frequent complex queries (joins and aggregations), but it also experiences a significant read-heavy workload. Which design choice best improves read performance while keeping relational features?

Accepted Answer

Add read replicas to an RDS or Aurora cluster and keep the primary for writes.. Adding read replicas to an RDS or Aurora cluster offloads read traffic from the primary instance, improving read performance for complex queries (joins and aggregations) while preserving the relational data model. Aurora automatically scales read replicas and uses a shared storage volume, making this highly efficient for read-heavy workloads.

Answer

Use DynamoDB with a single partition key and avoid indexes to keep writes simple.

Answer

Store the data in S3 and query it directly from the application without a database.

Answer

Switch the database to DynamoDB but keep using the same relational SQL queries and joins.

Question 14

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 ensures each user's events are stored in a separate partition, distributing the workload evenly and avoiding hot partitions. Adding `event_time` as the sort key allows DynamoDB to efficiently retrieve events for a given user in sorted order using a Query operation, which is both fast and cost-effective.

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 15

Based on the exhibit, which EBS volume type should the team use to meet the performance need at lower cost than overprovisioning capacity?

Accepted Answer

Use gp3 and provision the needed IOPS independently of volume size.. The gp3 volume type allows you to provision baseline performance of 3,000 IOPS and 125 MiB/s regardless of volume size, and you can independently increase IOPS up to 16,000 and throughput up to 1,000 MiB/s without needing to add more storage capacity. This decoupling of performance from size means you can meet the required IOPS at a lower cost compared to gp2, where performance scales with volume size and often forces overprovisioning of capacity to achieve the needed IOPS.

Answer

Use sc1 because it is optimized for infrequent access and large objects.

Answer

Use st1 because it provides high throughput for streaming data.

Answer

Use standard magnetic storage because it is compatible with all EC2 instances.