SAA-C03 Exam Dumps : AWS Certified Solutions Architect - Associate (SAA-C03)

The problem is that documents are stored on instance-local storage, so once the site scales horizontally, users may land on an instance that does not have the requested file. Amazon EFS is the best fit because AWS documents that EFS provides shared file storage with concurrent access from multiple EC2 instances and is accessible from all Availability Zones in the Region. That lets every web server read the same document set without changing to an object-storage pattern. The cron-based answers introduce delay and inconsistency, and S3 would require a bigger application-path change than the shared file system approach. For the least disruptive and most reliable restoration of access across multiple EC2 instances, mounting a single EFS file system on all instances is the right solution.

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Application Load Balancer (ALB): ALB is suitable for routing HTTP/HTTPS traffic to the application servers. It provides advanced routing features and integrates well with Auto Scaling groups.

Target Group Configuration:

Create a target group for the application servers and register the Auto Scaling group with this target group.

Configure the ALB to forward requests from the web servers to the application servers.

Security Group Setup:

Configure the security group of the application servers to only allow traffic from the web servers ' security group.

This ensures that only the web servers can access the application servers, meeting the requirement to limit access.

Benefits:

Security: Using security groups to restrict access ensures a secure environment where only intended traffic is allowed.

Scalability: ALB works seamlessly with Auto Scaling groups, ensuring the application can handle varying loads efficiently.

The key requirements are (1) MySQL compatibility for existing applications and (2) the ability to scale automatically during demand spikes for a transactional workload. Amazon Aurora (MySQL-compatible) satisfies compatibility while providing managed database capabilities designed for high performance and scalability. Using AWS Database Migration Service (DMS) is operationally efficient for migration because it supports moving data from on-premises databases to AWS with options for continuous replication to minimize downtime, which is commonly required for transactional systems.

Turning on Aurora Auto Scaling (for Aurora Replicas) allows the database tier to automatically add or remove read replicas based on demand, which helps absorb increased read traffic without manual intervention. This meets the “scale automatically” requirement more directly than simply scaling storage. (Write scaling is addressed through Aurora’s architecture and capacity planning; for many workloads, scaling reads is the dominant elasticity need.)

Option A only mentions configuring storage scaling, which does not address compute scaling during load increases; RDS storage autoscaling helps prevent running out of space but does not automatically add compute capacity in response to demand. Option B is incorrect because Amazon Redshift is a data warehouse designed for analytics/OLAP, not a transactional MySQL OLTP replacement, and mysqldump to Redshift does not preserve application compatibility. Option D changes the data model by migrating to DynamoDB, which is not MySQL-compatible and would require application redesign—violating the compatibility requirement.

Therefore, C best satisfies compatibility and automatic scaling needs while using managed services that reduce operational overhead during and after migration.