Amazon Elastic File System

File storage that can be shared across multiple servers.

A managed NFS file storage that can be shared from multiple EC2 instances and Lambda. Provides file-level read and write access.

• Shared file storage for multiple EC2 instances
• Content sharing
• Shared storage for Linux workloads

• A file storage service
• Accessible from multiple Availability Zones
• Accessed via NFS

• Design mount targets per subnet
• Choose between EFS Standard and One Zone based on use case
• Understand throughput modes

Amazon EFS (Elastic File System) is a fully managed NFS (Network File System) file storage service that can be mounted and shared simultaneously by multiple EC2 instances and Lambda functions. From the OS perspective, it is mounted as an ordinary file system, allowing multiple clients to read from and write to the same files concurrently. Capacity grows and shrinks automatically based on usage, eliminating the need to provision storage in advance. The major difference from EBS is that by placing a "mount target" in each subnet across multiple AZs, EC2 instances in multiple AZs can access the same file system. The storage classes have a two-tier structure: "Standard" (multi-AZ redundancy / standard for typical web and application workloads) and "One Zone" (single-AZ redundancy / lower cost / suited for development and testing), each combined with Infrequent Access (IA) lifecycle management that automatically migrates infrequently accessed data to a lower-cost tier. With Lifecycle Management, you can set rules such as "move to the IA tier if not accessed for 30 days", reducing costs for datasets with skewed access patterns. Throughput modes can be chosen from Bursting (auto-scales proportionally to capacity), Elastic, or Provisioned (explicitly reserved). Typical configurations in practice include shared media file storage across multiple EC2 instances, shared web content, CMS `uploads/` directory sharing, shared scratch space for Linux workloads, and shared model files read from Lambda container images. The differentiation among the three options of S3 (object storage / accessed via HTTP API), EBS (block storage attached to a single EC2 instance), and EFS (file storage NFS-mounted from multiple EC2 instances) is a frequent organizing point both in exams and in practice. In security operations, restrict NFS (TCP 2049) traffic to only the necessary clients via Security Groups, enable encryption at rest (with KMS integration) and encryption in transit (TLS), and use EFS access points to control subpath and user permissions within the file system.

• Amazon EFS (AWS Official)
• What is Amazon EFS (AWS Official Documentation)
• Amazon EFS Performance (AWS Official Documentation)

Last updated: 2026-06-01