Amazon Elastic File System (Amazon EFS) is a fully managed, scalable, and serverless NFS (Network File System) file system specifically designed for use with AWS services and on-premises resources. It enables companies to create and configure file systems that can be accessed from multiple Amazon EC2instances simultaneously, making it ideal for use cases that require shared file storage for AWS compute services.

Why Amazon EFS Fits the Requirements:

Managed Service: Amazon EFS is a fully managed file storage service that simplifies the process of setting up and managing NFS file systems.

Scalability and Elasticity: EFS automatically scales to accommodate the storage needs of applications, without the need to provision or manage storage capacity.

NFS Compatibility: Amazon EFS natively supports the NFSv4 protocol, making it compatible with a wide range of applications and workloads that require NFS access.

Integration with AWS Compute Services: EFS integrates seamlessly with Amazon EC2 and other AWS services, providing a shared file storage solution across multiple instances and services within the AWS cloud environment.

Why Other Options Do Not Fit:

A. Amazon Elastic Block Store (Amazon EBS): While EBS provides block-level storage that can be attached to individual EC2 instances, it is not a file system, nor does it provide managed NFS file storage capabilities. EBS is designed for single-instance access rather than shared file access across multiple instances.

B. AWS Storage Gateway Tape Gateway: Tape Gateway is designed for archival purposes and allows companies to store virtual tape backups in Amazon S3 or Glacier. It does not support NFS file storage and is not intended for regular compute access.

C. Amazon S3 Glacier Flexible Retrieval: Amazon S3 Glacier is optimized for data archiving and long-term storage of infrequently accessed data, but it does not provide NFS file system capabilities, nor is it suitable for high-performance access needs associated with compute services.

For more details, you can refer to theAWS Cloud Practitioner Essentialscontent, specifically the modules onStorage Serviceswhere Amazon EFS is covered as the managed NFS file storage solution offered by AWS.