Amazon Web Services SAA-C03 - AWS Certified Solutions Architect - Associate (SAA-C03)

DynamoDB Accelerator (DAX) is a fully managed, in-memory cache for DynamoDB that delivers up to a 10x performance improvement—even at millions of requests per second. DAX requires minimal changes to existing applications and offloads the read workload from DynamoDB during report generation.

Reference Extract:

"DAX provides in-memory acceleration for DynamoDB tables, reducing response times from milliseconds to microseconds with minimal application changes."

Source: AWS Certified Solutions Architect – Official Study Guide, DynamoDB and Performance section.

To analyze the performance of the web application with granularity of no more than 2 minutes, enablingdetailed monitoringon EC2 instances is the best solution. By default, CloudWatch provides metrics at a 5-minute interval. Enabling detailed monitoring allows you to collect metrics at 1-minute intervals, which will give you the level of granularity you need to analyze performance during peak traffic.

Amazon CloudWatch metrics can then be used to analyze CPU utilization, memory usage, disk I/O, and network throughput, among other performance-related metrics, at the desired granularity.

Option A: Sending CloudWatch logs to Redshift for analysis is unnecessary and overcomplicated for simple performance analysis, which can be done using CloudWatch metrics alone.

Option C: Fetching EC2 logs via Lambda adds complexity, and CloudWatch metrics already provide the required data for performance analysis.

Option D: Sending logs to S3 and using Redshift for analysis is also more complex than necessary for simple performance monitoring.

AWS References:

Monitoring Amazon EC2 with CloudWatch

Amazon CloudWatch Detailed Monitoring

AWS Step Functions supports long-running workflows and error retries, making it ideal for a job composed of many tasks. Integration with EventBridge allows automatic triggering from S3 events. This setup is resilient and supports up to 1-year execution duration.

AWS DataSync provides managed, incremental, parallelized transfers between EFS file systems across Regions, supporting scheduled or continuously running tasks with automatic change detection, encryption in transit, and integrity verification. You can configure two tasks in opposite directions (bi-directional) to achieve two-way synchronization with high availability using agents in each Region and EFS locations connected via VPC endpoints. Native EFS replication (B) is one-way (read-only target) and not intended for active/active two-way sync. Options A and D rely on custom rsync and cross-Region mounts or SFTP, which introduce operational overhead, latency, and fail to provide resilient, managed synchronization. DataSync minimizes operational burden while delivering fault-tolerant, scalable, cross-Region EFS sync.

CloudFront Signed Cookies:

CloudFront signed cookies allow the company to provide access to premium users while maintaining a single, consistent URL.

This approach is simpler and more scalable than managing presigned URLs for each file.

Incorrect Options Analysis:

Option A: Using EC2 and EBS increases complexity and cost.

Option B: Managing presigned URLs for each file is not scalable.

Option D: CloudFront signed URLs require unique URLs for each file, which does not meet the requirement for a single URL.

AWS Config is a service designed to assess, audit, and evaluate the configurations of AWS resources. It continuously monitors and records your AWS resource configurations and allows you to automate the evaluation of recorded configurations against desired configurations. By starting a configuration recorder, AWS Config will capture changes to supported resource types as configuration items—without the need to modify any of the existing resources. This provides a full history of configuration changes and is specifically intended for exactly this use case.

AWS Documentation Extract:

“AWS Config provides a detailed view of the configuration of AWS resources in your AWS account. This includes how the resources are related to one another and how they were configured in the past so you can see how the configurations and relationships change over time.”

“You can start the configuration recorder, which will record the configuration changes of the supported resources in your AWS account.”

(Source: AWS Config documentation, What is AWS Config?)

Other options:

B: CloudFormation drift detection only works for resources created and managed by CloudFormation and requires stacks.

C: Amazon Detective is used for analyzing and investigating security findings, not for resource configuration tracking.

D: AWS Audit Manager is used for automating evidence collection to help with audits, not for tracking resource configurations.

Option Ais the most automated and cost-efficient solution for exporting data to S3 for analytics.

Option Binvolves manual setup of Streams to S3.

Options C and Dintroduce complexity with EMR.

Amazon EMR on EC2 supports “runtime roles (application-scoped IAM roles)” so each application/step assumes its own IAM role with least-privilege S3 access. You enable this via an EMR security configuration by setting “EnableApplicationScopedIAMRole = true.” The EMR core/Task nodes run under the cluster’s EC2 instance profile; therefore the instance profile must be permitted to “sts:AssumeRole” into the defined EMR runtime roles, and each runtime role must trust the instance profile (trust policy principal is the instance profile role). This design limits each job’s S3 scope via role policies and enforces per-job access segregation. Option B reverses the trust (incorrect). Option E trusts the EMR service role (not used to assume runtime roles). Option F is unrelated (encryption in transit). The correct trio is to enable application-scoped roles (A), authorize the instance profile to assume them (C), and configure the runtime roles’ trust relationship to allow that assumption (D).

AWS Key Management Service (AWS KMS) provides multi-Region keys, allowing the same key to be used across Regions without managing your own hardware or key replication.

Multi-Region keys are fully managed and support attribute-based access control (ABAC) using tags and condition keys.

CloudHSM (Options C and D) requires full key lifecycle management, synchronization, and hardware operations, resulting in significantly higher overhead.

Imported key material (Option B) increases key-management responsibility.

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For globally distributed consumers of REST APIs, API Gateway edge-optimized endpoints “route requests to the nearest CloudFront edge location, which then forwards them to your API in the [home] Region,” reducing latency for users worldwide and scaling automatically for unknown or spiky traffic. By contrast, Regional endpoints are intended for clients within the same or nearby Region and do not provide global edge acceleration. AWS Lambda provides automatic scaling for serverless backends; latency can be further reduced by right-sizing memory (which also increases CPU) and, when needed, enabling provisioned concurrency to keep functions initialized and eliminate cold starts for critical paths. Using NLBs across Regions is not serverless and adds operational complexity without CloudFront edge acceleration. Therefore, combining API Gateway edge-optimized REST APIs with Lambda meets the requirements of minimal global latency and unknown initial traffic.

To improve read performance for a MySQL-based RDS database under load, you can:

Use Read Replicas: Amazon RDS supports MySQL read replicas, which help offload read operations from the primary database, improving performance during high traffic.

Use ElastiCache (Memcached): Adding an in-memory cache layer using Amazon ElastiCache reduces the load on the RDS instance by serving frequent queries directly from memory, especially when data is not updated often.

Option A (AWS WAF) is for web security, not database performance. Option D relates to storage optimization, not query latency. Option E would require re-architecting from relational to NoSQL, which is unnecessary and disruptive.

AmazonKinesis Data Streamsis the best choice for this scenario:

Message throughput: Kinesis Data Streams supports high throughput with enhanced fan-out and dedicated throughput for consumers.

Large message size: Supports message sizes up to 1 MB, meeting the 500 KB requirement.

Message retention: Data streams can retain messages for up to 365 days.

Strict ordering: Guarantees message ordering within shards.

Why Other Options Are Not Ideal:

Option B:

While SQS FIFO supports strict ordering, SNS topics do not. SNS also does not natively support message retention or strict ordering across consumers.Does not meet requirements.

Option C:

EventBridge does not provide strict ordering guarantees or message retention beyond 24 hours.Does not meet requirements.

Option D:

SNS topics with Data Firehose are not designed for use cases requiring strict ordering or long message retention.Does not meet requirements.

AWS References:

Amazon Kinesis Data Streams:AWS Documentation - Kinesis Data Streams

AWS Messaging Services Comparison:AWS Documentation - Messaging Services

Explanation (AWS Docs):

DynamoDB has a built-in feature called Time to Live (TTL) which automatically deletes expired items without manual intervention. This requires adding a timestamp attribute and setting a TTL on the table. This is the lowest operational overhead approach.

“You can use DynamoDB TTL to automatically delete items after a specified time, reducing storage costs and administrative overhead.”

— DynamoDB TTL

Amazon FSx for Lustre is the ideal solution for high-performance computing (HPC) workloads that require parallel access to a shared file system with low latency. FSx for Lustre is designed specifically to meet the needs of such workloads, offering sub-millisecond latencies, which makes it well-suited for the 1 ms latency requirement mentioned in the question.

Here is why FSx for Lustre is the best fit:

Parallel File System: FSx for Lustre is a parallel file system that can scale across hundreds of Amazon EC2 instances, providing high throughput and low-latency access to data. It is optimized for processing large datasets in parallel, which is essential for HPC workloads.

Low Latency: FSx for Lustre is capable of providing access latencies well within 1 ms, making it ideal for performance-sensitive workloads like HPC.

Seamless Integration with Amazon S3: FSx for Lustre can be linked to an Amazon S3 bucket. This integration allows data to be imported from S3 into FSx for Lustre before the workload begins and exported back to S3 after processing. This feature is crucial for manual postprocessing because it enables engineers to access the dataset in S3 after processing.

Performance: FSx for Lustre is built for workloads that require high performance, such as machine learning, analytics, media processing, and financial simulations, which are typical for HPC environments.

In contrast:

Amazon EFS (Option A): While EFS provides shared file storage and scales across multiple EC2 instances, it does not offer the same level of performance or sub-millisecond latencies as FSx for Lustre. EFS is more suited for general-purpose workloads, not high-performance computing.

Mounting S3 as a file system (Option B and D): S3 is object storage, not a file system designed for low-latency access and parallel processing. Mounting S3 buckets directly or using AWS Resource Access Manager to share the bucket would not meet the low-latency (1 ms) or performance requirements needed for HPC workloads.

Therefore, Amazon FSx for Lustre (Option C) is the most appropriate and verified solution for this scenario.

AWS References:

Amazon FSx for Lustre

Best Practices for High Performance Computing (HPC)

Amazon FSx and Amazon S3 Integration

To improve the performance of the primary RDS PostgreSQL database during business hours and reduce the load, the best solution is to create aread replicain the same region (us-east-1). This will offload the read-heavy operations (like generating reports) to the replica, reducing the burden on the primary instance, which improves overall performance. Additionally, read replicas provide near real-time replication, making them ideal for real-time reporting use cases.

Option A (cross-Region read replica): This adds unnecessary latency for real-time reporting and increased costs due to cross-region data transfer.

Option B (Multi-AZ): Multi-AZ deployments are for high availability and disaster recovery but won’t offload the read traffic, as the standby database cannot serve read requests.

Option C (AWS DMS replication): This adds complexity and is not as cost-effective as using an RDS read replica for the same region.

AWS References:

Amazon RDS Read Replicas

Amazon RDS Performance Best Practices