SAA-C03 Design High-Performing Architectures Practice Test 14 — 15 Questions

Question 1

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.

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

Accepted Answer

Point read-only queries to the Aurora reader endpoint instead of the writer endpoint.. 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 2

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 3

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 4

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 5

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

Question 6

A read-heavy document portal repeatedly queries the same product catalogue data from DynamoDB with millisecond latency requirements. Which service can reduce read latency and table load?

Accepted Answer

DynamoDB Accelerator (DAX). DynamoDB Accelerator (DAX) is a fully managed, in-memory cache for Amazon DynamoDB that delivers up to 10x read performance improvement by caching frequently accessed data. For a read-heavy workload querying the same product catalogue data, DAX reduces read latency to microseconds and offloads read requests from the DynamoDB table, lowering consumed read capacity units and table load.

Answer

Amazon Kinesis Data Firehose

Answer

S3 Transfer Acceleration

Answer

AWS Glue Data Catalog

Question 7

A analytics dashboard uses RDS MySQL and receives many read-only reporting queries that slow down the primary database. What should the architect add?

Accepted Answer

RDS read replica and route reporting queries to it. Adding an RDS read replica offloads read-heavy reporting queries from the primary MySQL instance, preserving write performance. The read replica asynchronously replicates data using MySQL's native binlog replication, and routing reporting queries to its endpoint reduces contention on the primary.

Answer

S3 lifecycle policy

Answer

Multi-AZ standby and route reads to the standby

Answer

A larger NAT gateway

Question 8

A media archive requires consistent high IOPS for a transactional database on EC2. Which EBS volume type is most suitable?

Accepted Answer

Provisioned IOPS SSD such as io2. The scenario requires consistent high IOPS for a transactional database, which demands low-latency, predictable performance. Provisioned IOPS SSD volumes like io2 are designed specifically for such workloads, offering up to 256,000 IOPS per volume with 99.999% durability, making them the most suitable choice for consistent high IOPS.

Answer

st1 Throughput Optimized HDD

Answer

Instance store only

Answer

sc1 Cold HDD

Question 9

A telemetry pipeline uses an Application Load Balancer in one Region. Global users need lower network latency to the application without caching dynamic responses. What should be considered?

Accepted Answer

AWS Global Accelerator. AWS Global Accelerator uses the Anycast IP address concept to route traffic through the AWS global network to the optimal endpoint, reducing latency and jitter for global users. It does not cache content, making it ideal for dynamic responses that cannot be cached, and it integrates directly with an Application Load Balancer in a single Region.

Answer

S3 Cross-Region Replication

Answer

CloudFront only with long TTLs

Answer

AWS Backup cross-Region copy

Question 10

A video platform uses Amazon Aurora. The workload has many short-lived database connections from Lambda functions, causing connection storms. What should be added?

Accepted Answer

RDS Proxy. RDS Proxy sits between Lambda functions and the Aurora database, pooling and reusing database connections. This prevents the Lambda functions from overwhelming the database with many short-lived connections, which can cause connection storms and degrade performance. RDS Proxy also reduces the overhead of establishing new connections and improves scalability.

Answer

S3 Select

Answer

An internet gateway

Answer

A larger Route 53 hosted zone

Question 11

A retail API uses EC2 instances behind an ALB. CPU is consistently high during peak traffic, and request latency rises. What should be configured?

Accepted Answer

Auto Scaling policy based on an appropriate CloudWatch metric. An Auto Scaling policy based on an appropriate CloudWatch metric (such as CPUUtilization or ALBRequestCountPerTarget) dynamically adds or removes EC2 instances to match demand. This directly addresses the high CPU and rising latency by distributing the load across more instances, preventing performance degradation during peak traffic.

Answer

S3 Object Lock

Answer

A VPC endpoint for CloudWatch only

Answer

Disable health checks

Question 12

A document portal needs low-latency full-text search across product descriptions and filtered attributes. Which managed service is most suitable?

Accepted Answer

Amazon OpenSearch Service. Amazon OpenSearch Service is purpose-built for full-text search, log analytics, and real-time application monitoring. It provides low-latency indexing and querying of unstructured and semi-structured data, making it ideal for searching product descriptions and filtering attributes. The service uses a RESTful API and supports advanced query DSL for complex search operations.

Answer

AWS Config

Answer

Amazon EFS

Answer

Amazon SQS

Question 13

A high-volume analytics dashboard writes streaming click events that must be processed by multiple independent consumers. Which service is most appropriate?

Accepted Answer

Amazon Kinesis Data Streams. Amazon Kinesis Data Streams is the most appropriate service because it is designed for real-time streaming data ingestion and can be consumed by multiple independent consumers in parallel. Each shard within a Kinesis stream supports up to 5 read transactions per second and a total data read rate of 2 MB per second, allowing multiple consumer applications to process the same stream of click events concurrently without interfering with each other.

Answer

Amazon Route 53

Answer

Amazon EBS

Answer

AWS DataSync

Question 14

A global mobile game backend 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 files) at edge locations worldwide. By distributing content closer to users, it significantly reduces latency and improves load times for a global audience, making it the most effective solution for this use case.

Answer

RDS read replicas

Answer

A larger S3 bucket

Answer

An EC2 Auto Scaling group in one Region

Question 15

A DynamoDB table for a travel booking site 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 low-cardinality partition key like the current date concentrates all writes into a single partition, causing throttling when write demand exceeds that partition's 1,000 WCU limit. A higher-cardinality key (e.g., combining date with user ID or session ID) distributes writes evenly across multiple partitions, allowing the table to use its full provisioned write capacity without throttling.

Answer

Create a global secondary index with the same date key

Answer

Move the table to S3 Glacier Instant Retrieval

Answer

Reduce the table's write capacity