SAA-C03 Design High-Performing Architectures Practice Test 10 — 15 Questions

Question 1

Based on the exhibit, an application repeatedly reads the same DynamoDB items with extremely low latency requirements. The business can tolerate data that is a few seconds stale. Which architecture change best improves read performance?

Accepted Answer

Add a DynamoDB Accelerator (DAX) cluster in front of the table.. Adding a DynamoDB Accelerator (DAX) cluster provides an in-memory cache that can reduce read latencies to microseconds for frequently accessed items, while still allowing for eventual consistency and tolerating a few seconds of staleness. DAX is specifically designed for this use case, handling cache hits without any application code changes and offloading read traffic from the DynamoDB table.

Answer

Increase the table's sort key cardinality while keeping the same read pattern.

Answer

Switch the table to provisioned mode with auto scaling disabled.

Answer

Move the session data to Amazon EFS so the application can read it from shared files.

Question 2

Based on the exhibit, a serverless API on AWS Lambda experiences a predictable cold-start penalty every weekday at 09:00 UTC when a marketing campaign begins. The team wants the first requests to stay fast while minimizing extra cost during quiet periods. What is the best approach?

Accepted Answer

Enable provisioned concurrency on the published version and schedule it to scale up shortly before the spike.. Provisioned concurrency pre-warms a specified number of Lambda execution environments so that incoming requests do not incur a cold start. By scheduling the provisioned concurrency to scale up just before the 09:00 UTC spike and scale down afterward, the team eliminates the cold-start penalty during the campaign while minimizing cost during quiet periods. This directly addresses the predictable, time-bound traffic pattern without requiring code changes or over-provisioning.

Answer

Increase the Lambda timeout so cold starts have more time to complete.

Answer

Move the function behind an Application Load Balancer to improve warm-up behavior.

Answer

Increase the function memory to the maximum value and leave concurrency unchanged.

Question 3

Based on the exhibit, a distributed analytics workload runs on 12 EC2 instances in one Availability Zone. The nodes exchange thousands of small messages per second and require the lowest possible intra-cluster latency and jitter. Which EC2 placement strategy is the best fit?

Accepted Answer

Cluster placement group, because it places instances physically close together in one Availability Zone.. A cluster placement group is the best choice because it places all 12 EC2 instances in a single Availability Zone within the same high-bandwidth, low-latency logical segment of the network. This minimizes the physical distance and network hops between nodes, achieving the lowest possible intra-cluster latency and jitter required for the thousands of small messages exchanged per second.

Answer

Spread placement group, because it places each instance on distinct underlying hardware.

Answer

Partition placement group, because it isolates nodes across rack partitions.

Answer

Move the workload behind an Application Load Balancer so node-to-node traffic is balanced more efficiently.

Question 4

Based on the exhibit, a single EC2 instance hosts a latency-sensitive cache that performs sustained random reads and writes to persistent block storage. The current EBS volume is a general-purpose SSD, but BurstBalance is repeatedly depleted and p95 I/O latency has risen above 20 ms. The workload needs more than 16,000 sustained IOPS. Which change is the best fix?

Accepted Answer

Replace the volume with an io2 EBS volume and provision the required IOPS.. The workload requires more than 16,000 sustained IOPS with low latency, and the gp2 volume's burst credits are exhausted, causing high latency. An io2 Block Express or io2 volume can be provisioned with the exact IOPS needed (up to 256,000 IOPS) and provides consistent single-digit millisecond latency, making it the best fix for this latency-sensitive, sustained I/O workload.

Answer

Move the data to Amazon S3 so the instance can read and write objects directly.

Answer

Keep gp2 and increase the instance size to a compute-optimized family.

Answer

Enable Amazon EFS with bursting throughput mode for the cache data.

Question 5

A media company serves versioned JavaScript and CSS files from Amazon S3 through CloudFront. After each release, the cache hit ratio drops sharply because the same distribution also fronts a personalized API path, and the current cache policy forwards cookies, all query strings, and several headers to every origin request. The static assets already use content-hashed filenames. Which two changes will most directly improve cache hit ratio for the static assets without changing the application behavior? Select two.

Accepted Answer

Create a dedicated cache behavior for the static asset path that excludes cookies, query strings, and unneeded headers from the cache key.. Option A is correct because creating a dedicated cache behavior for the static asset path (e.g., /static/*) allows you to configure a cache policy that excludes cookies, query strings, and unneeded headers from the cache key. Since the static assets use content-hashed filenames, they are immutable and do not vary by user-specific attributes. By removing these variables from the cache key, CloudFront can serve the same cached object to all users, drastically improving the cache hit ratio.

Answer

Increase the size of the S3 bucket’s underlying storage to absorb more origin traffic.

Answer

Add Lambda@Edge logic to append a timestamp to every asset request so updates are always fetched immediately.

Answer

Disable compression so CloudFront can treat each object as a separate cache entry.

Question 6

A retail analytics table stores events in Amazon DynamoDB with partition key tenantId and sort key eventTime. During a promotion, one tenant generates most writes and repeatedly polls the same latest-status items, causing throttling on a single partition key and high latency on reads. The business can tolerate read results that are a few seconds stale. Which two changes will most effectively reduce throttling and latency? Select two.

Accepted Answer

Introduce write sharding by adding a bounded random suffix to the hot tenant partition key and fan out reads across the shards.. Option A is correct because write sharding distributes the hot tenant's writes across multiple partitions by appending a bounded random suffix to the partition key, preventing a single partition from throttling. Reads then fan out across all shards and aggregate results, which is acceptable since the business tolerates a few seconds of staleness. This directly addresses the single-partition bottleneck without changing the overall data model.

Answer

Keep the same key design and increase only the table’s provisioned RCUs and WCUs.

Answer

Replace the table reads with a Scan operation to distribute the load across all partitions.

Answer

Move the table to another Availability Zone so the hot tenant uses a different storage node.

Question 7

A distributed analytics engine runs 12 EC2 instances in one Availability Zone. The nodes exchange thousands of tiny messages per second and must keep jitter as low as possible. The current design launches the instances across multiple placement groups and uses general-purpose burstable instances. Which two changes will most directly lower east-west network latency and variability? Select two.

Accepted Answer

Move all instances into a cluster placement group.. A cluster placement group provides a low-latency, high-bandwidth network connection by placing instances in a single Availability Zone within the same logical rack or cluster. This minimizes the physical distance and network hops between instances, directly reducing east-west latency and jitter for the thousands of tiny messages per second.

Answer

Spread the instances across three Availability Zones for better fault tolerance.

Answer

Front the nodes with an Application Load Balancer to balance the internal messages.

Answer

Store the messages on EBS volumes so the nodes avoid network communication.

Question 8

A serverless checkout API uses AWS Lambda behind API Gateway. Every weekday at 09:00 UTC, marketing triggers a predictable surge. The first few minutes after each surge show cold-start latency, but traffic volume is forecastable and the business wants stable p95 latency. Which two changes should the team implement? Select two.

Accepted Answer

Publish a Lambda version and attach provisioned concurrency to an alias that points to that version.. Provisioned concurrency keeps a specified number of Lambda execution environments initialized and ready to respond immediately, eliminating cold starts for predictable traffic patterns. By publishing a Lambda version and attaching provisioned concurrency to an alias pointing to that version, the team ensures that the surge at 09:00 UTC is handled without cold-start latency, stabilizing p95 latency.

Answer

Increase the Lambda timeout so the function has more time to initialize during the spike.

Answer

Double the memory size during the spike without changing the concurrency model.

Answer

Move the function into more Availability Zones so the platform can spread cold starts across regions.

Question 9

A partner integration sends a custom binary TCP protocol to a service running on EC2 instances in private subnets. The partners require static endpoint IPs for allowlisting, and the application must see the original client source IP for rate limiting. Which two changes best fit the protocol and network requirements? Select two.

Accepted Answer

Replace the Application Load Balancer with a Network Load Balancer.. A Network Load Balancer (NLB) is required because it supports TCP traffic natively at Layer 4, which is necessary for a custom binary TCP protocol that cannot be interpreted by an Application Load Balancer (ALB) at Layer 7. Additionally, an NLB preserves the original client source IP address by default when used with targets in private subnets, meeting the requirement for rate limiting based on the client IP. Static IP addresses can be assigned to the NLB via Elastic IPs, satisfying the partner's need for static endpoint IPs for allowlisting.

Answer

Put the service behind API Gateway REST API and use Lambda integration.

Answer

Use CloudFront to cache the binary packets at edge locations.

Answer

Terminate the traffic with an Amazon RDS proxy to stabilize the connections.

Question 10

An application uses Amazon Aurora MySQL. CloudWatch shows the writer instance near 85% CPU while the only reader instance averages 15% CPU. Trace logs show that all SELECT statements still target the writer endpoint. The workload is read-heavy, and the application already tolerates eventual consistency for reads. Which two changes will best increase total read throughput without a schema redesign? Select two.

Accepted Answer

Point read-only queries to the Aurora reader endpoint instead of the writer endpoint.. Option A is correct because the Aurora reader endpoint is designed to distribute read-only connections across all available Aurora Replicas, offloading SELECT queries from the writer instance. Currently, all SELECT statements target the writer endpoint, causing the writer's CPU to be at 85% while the reader instance is underutilized at 15%. By redirecting read traffic to the reader endpoint, the writer's CPU load decreases, and the existing reader instance can handle more read throughput without any schema changes.

Answer

Convert the cluster to a single-AZ RDS MySQL instance to reduce replication overhead.

Answer

Replace the writer endpoint with the instance endpoint of the primary node to speed up SELECT queries.

Answer

Add Amazon ElastiCache and move all database writes into the cache layer.

Question 11

Multiple EC2 instances in different Availability Zones need concurrent read/write access to the same shared files. The files are actively modified by several application servers, and low-latency metadata operations matter more than extremely high aggregate throughput. Which two changes should the team make? Select two.

Accepted Answer

Use Amazon EFS instead of EBS or S3 for the shared file system.. Amazon EFS provides a fully managed, POSIX-compliant, shared file system that can be mounted concurrently by multiple EC2 instances across different Availability Zones (AZs). It supports concurrent read/write access with strong consistency, and its metadata operations are optimized for low latency, making it ideal for workloads where many application servers actively modify the same files. EBS cannot be shared across AZs, and S3 lacks POSIX semantics and low-latency metadata operations.

Answer

Use a single EBS Multi-Attach volume mounted read/write by all instances across AZs.

Answer

Store the files in S3 and mount them directly through the console as a shared network filesystem.

Answer

Place the files on instance store volumes so each server has faster local access.

Question 12

A nightly video rendering pipeline runs on Linux EC2 instances and is compatible with ARM64. The jobs are CPU-bound, checkpoint frequently, and can resume if interrupted. The business wants the best throughput per dollar for the batch window. Which two changes should the team make? Select two.

Accepted Answer

Use AWS Graviton-based instances for the render workers.. AWS Graviton-based instances use ARM64 architecture, which is explicitly compatible with the video rendering pipeline. They offer up to 40% better price-performance compared to comparable x86 instances for CPU-bound workloads, directly improving throughput per dollar. This makes option A correct for maximizing cost efficiency.

Answer

Use a single large x86 instance with On-Demand pricing to avoid interruptions.

Answer

Replace the batch workers with a Lambda function to eliminate instance management.

Answer

Move the workload to a spread placement group to increase cost efficiency.

Question 13

A media company serves versioned JavaScript and CSS files from an Amazon S3 origin through CloudFront. After each release, origin requests spike even though the files are public. Browser requests include a tracking cookie, an Authorization header, and a cache-busting query string that the site no longer needs. Which three changes will most improve the CloudFront cache hit ratio without exposing private content? Select three.

Accepted Answer

Rename each static asset with a content hash or release version in the filename before publishing.. Option A is correct because renaming static assets with a content hash or version in the filename ensures that each new release creates a unique object key in S3. This allows CloudFront to treat the new file as a distinct object, avoiding cache invalidation issues and enabling long-term caching of the old version. Without this, even with cache-busting query strings, CloudFront might still serve stale content or require frequent invalidations, reducing the cache hit ratio.

Answer

Enable CloudFront compression and configure the origin to return Cache-Control: no-store for all files.

Answer

Forward all viewer headers to the origin so CloudFront can personalize every request.

Question 14

A global video platform serves mostly static images and JavaScript files from an S3 origin. Users in distant countries report slow load times. What should improve performance most?

Accepted Answer

Amazon CloudFront distribution with the S3 bucket as origin. Amazon CloudFront is a content delivery network (CDN) that caches static content (images, JavaScript) at edge locations worldwide. By distributing content closer to users, it reduces latency and improves load times significantly compared to serving directly from a single S3 origin. This is the most effective solution for a global user base accessing static assets.

Answer

A larger S3 bucket

Answer

RDS read replicas

Answer

An EC2 Auto Scaling group in one Region

Question 15

A DynamoDB table for a retail API has a partition key based only on the current date. Write throttling occurs during business hours. What is the best design change?

Accepted Answer

Use a higher-cardinality partition key that distributes writes across partitions. Using a partition key based solely on the current date creates a 'hot partition' because all writes for that day target the same partition, leading to throttling. A higher-cardinality partition key (e.g., combining date with a unique attribute like user ID or order ID) distributes write traffic evenly across multiple partitions, allowing DynamoDB to utilize its full throughput capacity and eliminating throttling.

Answer

Create a global secondary index with the same date key

Answer

Reduce the table's write capacity

Answer

Move the table to S3 Glacier Instant Retrieval

SAA-C03 Design High-Performing Architectures Practice Test 10 — 15 Questions

Exhibit

SAA-C03 Design High-Performing Architectures Practice Test 10 — 15 Questions

Exhibit