Key points

• EFS provides shared durable POSIX file storage to supported compute, including Lambda through access points.
• VPC connectivity, mount targets, access points, roles, and file permissions all participate in access.

Best-known use cases

• Share POSIX files across multiple processing instances or containers.
• Provide persistent shared files to Lambda-based processing functions.

What candidates often confuse it with

• EFS is shared file storage; EBS is block storage for hosts and S3 is object storage.

Key takeaway

Choose EFS when multiple processing instances, containers, or functions need the same persistent file system.

Relevant exam tasks

• D1.4 — Task 1.4: Apply programming concepts
• 1.4.7 — Use and mount storage volumes from within Lambda functions.
• D2.1 — Task 2.1: Choose a data store
• 2.1.4 — Integrate migration tools into data processing systems (for example, AWS Transfer Family).

Learn more

• DEA-C01 in-scope services
• DEA-C01 Domain 1: Data Ingestion and Transformation
• DEA-C01 Domain 2: Data Store Management