AWS Certified Associate SAA-C03 Book

Amazon EFS is the best fit because it is a fully managed, elastic file storage service for Linux workloads, and it scales automatically without pre-provisioning capacity. AWS documentation states thatElastic throughputautomatically scales throughput up or down for spiky or unpredictable workloads, which matches the varying access pattern in the question. AWS also documents thatEFS lifecycle managementandEFS Intelligent-Tieringautomatically transition files between storage classes based on access patterns, which provides the native tiering requirement. FSx for Windows is not the right operating-system fit, and using EC2 plus EBS would require more manual storage management. Therefore,EFS with Elastic throughput and Intelligent-Tieringis the most cost-effective managed design. (AWS Documentation)

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AWS Lake Formation natively supports fine-grained access control, including:

Row-level security

Cell/column-level security

These are implemented through data filters and Lake Formation permissions on governed tables and views. This allows you to centrally define which users or groups can access which rows and which columns, including sensitive data fields, with minimal custom code or maintenance.

Why others are incorrect:

A: IAM alone does not provide row-level or cell-level data security inside Lake Formation tables.

C and D: Using Lambda to scrub or periodically remove sensitive data is complex, error-prone, and high overhead compared to built-in Lake Formation data filters.

Key Requirements:

Serverless architecture.

Handle traffic bursts with high availability.

Process orders asynchronouslyin the order they are received.

Analysis of Options:

Option A:Amazon SNS delivers messages to subscribers. However, SNS does not ensure ordering, making it unsuitable for FIFO (First In, First Out) requirements.

Option B:Amazon SQS FIFO queues support ordering and ensure messages are delivered exactly once. AWS Lambda functions can be triggered by SQS to process messages asynchronously and efficiently. This satisfies all requirements.

Option C:Amazon SQS standard queues do not guarantee message order and have " at-least-once " delivery, making them unsuitable for the FIFO requirement.

Option D:Similar to Option A, SNS does not ensure message ordering, and using AWS Batch adds complexity without directly addressing the requirements.

AWS References:

Amazon SQS FIFO Queues

AWS Lambda and SQS Integration

Amazon ElastiCache (Redis OSS) provides an in-memory cache that drastically improves read performance with minimal operational overhead.

It integrates easily with RDS and does not require schema or database changes.

EC2-based caching (Option C) increases management overhead.

DAX (Option D) accelerates DynamoDB only, not RDS.

Moving to DynamoDB (Option A) requires complete application and schema redesign.

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