SAA-C03 Design High-Performing Architectures Practice Test 1 — 15 Questions

Question 1

A Lambda function behind API Gateway has predictable traffic spikes every hour. The function does not need access to resources in a VPC, and p95 latency spikes are caused by cold starts during scale-out. Which two actions are most effective? Select two.

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Enable provisioned concurrency for the function.. Provisioned concurrency pre-warms a specified number of Lambda execution environments, eliminating cold starts for those instances. This directly addresses the p95 latency spikes caused by cold starts during predictable traffic spikes, as the function will have warm containers ready to handle incoming requests without the initialization delay.

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Set reserved concurrency to a low fixed number.

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Increase the Lambda timeout to 15 minutes.

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Add an SQS dead-letter queue to reduce startup latency.

Question 2

A team is splitting a new workload into two fronts. The first front serves HTTPS microservices that need host- and path-based routing plus health checks. The second front must handle TCP and UDP traffic for a real-time service and preserve static IP addresses for firewall allowlisting. Which two AWS load balancer choices best match these requirements? Select two.

Accepted Answer

Application Load Balancer. The Application Load Balancer (ALB) is correct because it supports host-based and path-based routing for HTTP/HTTPS traffic, which is essential for the microservices front. It also provides health checks at the target group level, enabling automatic routing away from unhealthy instances. ALB operates at Layer 7, making it ideal for the HTTPS microservices requirement.

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Amazon API Gateway

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Amazon CloudFront

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Gateway Load Balancer

Question 3

A distributed simulation launches 40 EC2 instances that exchange small packets frequently and are sensitive to cross-instance latency. The workload stays in one Availability Zone and can use the same instance family across nodes. Which two choices improve network performance the most? Select two.

Accepted Answer

Launch all instances in a cluster placement group.. A cluster placement group provides low-latency, high-bandwidth network connectivity by placing instances in a single Availability Zone within the same logical rack or cluster. This minimizes cross-instance latency and maximizes throughput for frequent small-packet exchanges, which is ideal for tightly coupled distributed simulations.

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Place the instances across several Availability Zones for higher aggregate resilience.

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Use a spread placement group to pack the instances tightly together.

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Put the workload behind CloudFront so internal node communication is faster.

Question 4

A company serves the same public content to many users through Amazon CloudFront. The origin is experiencing increased fetches because CloudFront cache hit rate is dropping. Most requests include an Authorization header and a custom header that changes per user. The response content is identical regardless of these headers. What change should the solutions architect make to restore a high cache hit rate?

Accepted Answer

Create a custom cache policy that excludes the Authorization header and the per-user changing custom header from the cache key.. CloudFront's default cache key includes the Authorization header and all custom headers, which causes unique cache entries for each user even though the content is identical. By creating a custom cache policy that excludes these headers from the cache key, CloudFront will treat requests with different header values as the same cached object, restoring a high cache hit rate and reducing origin fetches.

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Lower the TTL to a few seconds so cached objects expire sooner and origin fetches decrease.

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Disable caching for the affected paths so CloudFront always forwards all headers to the origin.

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Force all requests to use query-string based caching and include all headers in the cache policy for correctness.

Question 5

A marketing site serves versioned JavaScript and CSS files from Amazon S3 through CloudFront. Origin bandwidth costs are rising because CloudFront keeps revalidating objects and fetching too much content from the bucket. Which two changes most directly improve cache hit ratio and reduce origin load? Select two.

Accepted Answer

Use versioned object names and long cache TTLs for immutable assets.. Using versioned object names (e.g., app-v1.js, app-v2.js) combined with long cache TTLs (e.g., one year) tells CloudFront that these assets are immutable. Once cached, CloudFront never revalidates them, eliminating origin requests for unchanged files. This directly reduces origin bandwidth costs by preventing unnecessary fetches from S3.

Answer

Forward all cookies and query strings so each request is treated as unique.

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Switch the bucket to S3 Intelligent-Tiering to reduce CloudFront origin requests.

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Add more NAT Gateways to improve the speed of CloudFront origin fetches.

Question 6

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 full relational data model and SQL capabilities. Aurora’s distributed storage layer also allows replicas to serve reads with minimal replication lag, making this the optimal choice for read-heavy workloads that require relational features.

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

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

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

Question 7

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.. The cache-aside (lazy loading) pattern with TTL plus explicit invalidation ensures that after a write to DynamoDB, the stale Redis entry is removed, forcing the next read to fetch the updated profile from DynamoDB and repopulate the cache. This minimizes the window of inconsistency while keeping cache management simple and efficient for user profile workloads.

Answer

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

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

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

Question 8

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.

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

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

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

Question 9

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.

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Increase the function timeout to give more time for initialization.

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

Question 10

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.

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EBS st1 (throughput optimized HDD)

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EBS sc1 (cold HDD)

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EBS magnetic (legacy magnetic)

Question 11

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.. 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.

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

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

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

Question 12

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.. 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.

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

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

Question 13

A media platform serves global users through Amazon CloudFront and an S3 origin. Match each requirement on the left to the CloudFront configuration or behavior on the right.

Accepted Answer

Restrict access by geography: Geo Restriction. Geo restriction limits access by geography; origin groups enable failover or load balancing; Lambda@Edge customizes content based on device; edge locations reduce latency; AWS WAF mitigates DDoS; signed URLs secure private content.

Answer

Provide failover or load balancing: Lambda@Edge

Answer

Secure private content: Geo Restriction

Question 14

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.

Accepted Answer

Steady increase: Step scaling. Steady increase uses step scaling for gradual adjustments; sudden spikes are best handled by step scaling; cyclical patterns use scheduled scaling; consistent low traffic may need no scaling; unpredictable bursts use target tracking; gradual decrease uses simple scaling.

Answer

Sudden spike: Simple scaling

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Steady increase: Simple scaling

Question 15

A company runs a stateless web API on Amazon EC2 behind an Application Load Balancer. The team notices that during business hours, the ALB starts queueing requests and the average request latency rises. They want to scale out quickly and reliably based on demand, not CPU alone. Which Auto Scaling approach best matches this requirement?

Accepted Answer

Use target tracking scaling based on ALB request count per target.. Target tracking scaling based on ALB request count per target directly measures the load on each instance, allowing the Auto Scaling group to add or remove instances to maintain a target value. This approach scales out quickly and reliably based on actual demand (request queuing and latency), not just CPU, which aligns with the requirement to respond to rising latency and queueing during business hours.

Answer

Use a fixed-size Auto Scaling group and increase capacity manually once per hour.

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Scale based only on EC2 instance memory utilization, regardless of load.

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Use step scaling with a single threshold on average network-in bytes.