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Storage

Amazon EFS

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Amazon EFS

A fully managed, regional file storage service that provides POSIX-compliant shared file systems accessible via NFS. It operates by exposing file systems through mount targets in a VPC so multiple compute resources can concurrently mount the same filesystem. It normally fits in AWS architectures as a shared network file system for EC2, containers, and serverless functions requiring POSIX semantics.

🗂 Resource Category

Storage

🧠 Exam Memory Hook

Think: "POSIX shared file storage + network mounts in VPC = Amazon EFS"

📖 Ownership

Classification: AWS Managed Service

AWS responsibilities: AWS operates and maintains the underlying service control plane, storage infrastructure, network connectivity for mount targets, APIs, and the managed service platform; AWS is responsible for patching AWS-owned physical infrastructure and the managed service components that run Amazon EFS.

Customer responsibilities: The customer configures file system settings, access controls (security groups, IAM policies where applicable), NFS export and POSIX permissions, lifecycle policies, encryption key usage, backups, and monitors performance and capacity usage; the customer is responsible for data protection, data integrity, and application-level consistency.

Patching responsibilities: AWS patches the physical infrastructure and the managed service platform used to run Amazon EFS. The customer patches the guest operating system on EC2 instances, container images and their dependencies, application libraries, and customer-deployed applications. When compute is serverless or fully managed by AWS (for example AWS Lambda runtimes or Fargate managed infrastructure), AWS patches those managed runtimes according to those services' models, but the customer remains responsible for their code and packaged dependencies.

🏗 Typical Architecture

💡 Top 5 Features

  • POSIX-compliant shared file system accessible via NFSv4.1 and NFSv4.0
  • Automatically scales storage capacity as files are added or removed
  • Provides mount targets in VPC subnets to enable network-based mounts from compute resources
  • Supports encryption at-rest with AWS KMS and optional encryption in-transit for NFS
  • Offers selectable performance and throughput modes plus lifecycle management for infrequent access

✅ Top 5 Use Cases

  • Provide a shared POSIX filesystem for lift-and-shift legacy applications that require NFS-mounted storage across multiple instances.
  • Serve shared storage for container workloads that require a common filesystem for state or shared artifacts.
  • Host home directories or user file shares for distributed teams and development environments.
  • Store media assets and provide concurrent access to rendering or transcoding worker fleets.
  • Support analytics or batch processing clusters that require shared POSIX access to input and result files.

🏗 Architecture Placement

Amazon EFS is a regional, VPC-integrated file storage layer that is mounted by compute resources over the network using mount targets in subnets. Compute resources such as EC2 instances, containers, and supported serverless functions initiate NFS connections to mount targets, and management or backup services can call the EFS APIs or perform backups. Placement and access are determined by VPC network configuration, security groups, and NFS client configuration. EFS is not a global service and is accessed within the region where the file system exists.

🎯 Commonly Used With

- Amazon EC2
- Amazon ECS
- Amazon EKS
- AWS Lambda
- Amazon VPC

🌍 5 Real-World Examples

  • A media production environment using Amazon EFS to store shared video assets so render nodes across availability zones can read and write the same files, simplifying asset sharing.
  • A healthcare imaging pipeline mounting Amazon EFS from compute nodes to process and store intermediate image data while keeping POSIX file metadata intact for downstream tools.
  • A retail website serving product image assets from EC2 instances that mount Amazon EFS to provide a consistent file namespace for multiple web servers.
  • A research cluster using Amazon EFS to present a common filesystem to analysis jobs so scientists can access datasets and results from any compute node.
  • An education lab where student virtual desktops and containers mount Amazon EFS for persistent home directories and shared coursework files.

🎓 AWS Exam Clues

  • Use Amazon EFS when multiple instances or containers need concurrent POSIX-compliant file access over NFS.
  • If the workload requires a single-instance block device with low-level block access, choose Amazon EBS instead of EFS.
  • For object storage and large-scale static assets without POSIX semantics, consider Amazon S3 rather than EFS.
  • Consider performance and throughput modes when the workload requires high aggregate throughput or many concurrent clients.
  • Apply VPC security groups, mount target placement, and POSIX permissions when exam wording focuses on network access and file-level permissions.

📝 Quick Revision

Amazon EFS is a managed, POSIX-compliant network file system accessed via NFS that automatically scales capacity and is mounted by compute in a VPC. Use it when multiple hosts need concurrent file access; consider performance modes, VPC mount targets, encryption, and backup integration in production.

🏷 Keywords

NFSv4.1 • POSIX • Mount target • VPC • Elastic capacity • Lifecycle management • Infrequent Access • Performance modes • Throughput modes • Encryption at-rest • Encryption in-transit • AWS Backup