Amazon Elastic File System (EFS) FAQs

Q. What is Amazon Elastic File System?

Amazon EFS is a fully-managed service that makes it easy to set up and scale file storage in the Amazon cloud. With a few clicks in the AWS Management Console, you can create file systems that are accessible to Amazon EC2 instances via a file system interface (using standard operating system file I/O APIs) and that support full file system access semantics (such as strong consistency and file locking).

Amazon EFS file systems can automatically scale from gigabytes to petabytes of data without needing to provision storage. Tens, hundreds, or even thousands of Amazon EC2 instances can access an Amazon EFS file system at the same time, and Amazon EFS provides consistent performance to each Amazon EC2 instance. Amazon EFS is designed to be highly durable and highly available. With Amazon EFS, there is no minimum fee or setup costs, and you pay only for the storage you use.

 

Q. What use cases is Amazon EFS intended for?

Amazon EFS is designed to provide performance for a broad spectrum of workloads and applications, including Big Data and analytics, media processing workflows, content management, web serving, and home directories.

 

Q. When should I use Amazon EFS vs. Amazon Simple Storage Service (S3) vs. Amazon Elastic Block Store (EBS)?

Amazon Web Services (AWS) offers cloud storage services to support a wide range of storage workloads.

Amazon EFS is a file storage service for use with Amazon EC2. Amazon EFS provides a file system interface, file system access semantics (such as strong consistency and file locking), and concurrently-accessible storage for up to thousands of Amazon EC2 instances.

Amazon EBS is a block level storage service for use with Amazon EC2. Amazon EBS can deliver performance for workloads that require the lowest-latency access to data from a single EC2 instance.

Amazon S3 is an object storage service. Amazon S3 makes data available through an Internet API that can be accessed anywhere.

 

Q. Where is my data stored?

Please refer to Regional Products and Services for details of Amazon EFS service availability by region.

 

Q. How do I get started using Amazon EFS?

To use Amazon EFS, you must have an Amazon Web Services account. If you do not already have an AWS account, you can create one by clicking the “Try the Free Tier” button on the Amazon EFS detail page.

Once you have created an AWS account, please refer to the Amazon EFS Getting Started guide to begin using Amazon EFS. You can create a file system via the AWS Management Console, the AWS Command Line Interface (AWS CLI), and Amazon EFS API (and various language-specific SDKs).

 

Q. How do I access a file system from an Amazon EC2 instance?

To access your file system, you mount the file system on an Amazon EC2 Linux-based instance using the standard Linux mount command. Once you’ve mounted, you can work with the files and directories in your file system just like you would with a local file system.

Amazon EFS uses the NFSv4.1 protocol. For a step-by-step example of how to access a file system from an Amazon EC2 instance, please see the Amazon EFS Getting Started guide.

 

Q. What Amazon EC2 instance types and AMIs work with Amazon EFS?

Amazon EFS is compatible with all Amazon EC2 instance types and is accessible from Linux-based AMIs. You can mix and match the instance types connected to a single file system. For a step-by-step example of how to access a file system from an Amazon EC2 instance, please see the Amazon EFS Getting Started guide.

 

Q. How do I manage a file system?

Amazon EFS is a fully-managed service, so all of the file storage infrastructure is managed for you. When you use Amazon EFS, you avoid the complexity of deploying and maintaining complex file system infrastructure. An Amazon EFS file system grows and shrinks automatically as you add and remove files, so you do not need to manage storage procurement or provisioning.

You can administer a file system via the AWS Management Console, the AWS command-line interface (CLI), or the Amazon EFS API (and various language-specific SDKs). The Console, API, and SDK provide the ability to create and delete file systems, configure how file systems are accessed, create and edit file system tags, and display detailed information about file systems.

 

Q. How do I load data into a file system?

Amazon EFS file systems are mounted on an Amazon EC2 instance, so any data that is accessible to an Amazon EC2 instance can also be read and written to Amazon EFS. To load data that is not currently stored on the Amazon cloud, you can use the same methods you use to transfer files to Amazon EC2 today, such as Secure Copy (SCP). For more information about moving data to the Amazon cloud, please see the Cloud Data Migration page.

Q. How is Amazon EFS designed to provide high durability and availability?

Every file system object (i.e. directory, file, and link) is redundantly stored across multiple Availability Zones. In addition, a file system can be accessed concurrently from all Availability Zones in the region where it is located, which means that you can architect your application to failover from one AZ to other AZs in the region in order to ensure the highest level of application availability.

Mount targets themselves are designed to be highly available. When designing your application for high availability and failover to other Availability Zones, keep in mind that the IP addresses and DNS for your mount targets in each Availability Zone are static.

Q. How do I back up a file system?

Amazon EFS is designed to be highly durable. If you want to be able to revert to earlier versions of files to undo changes, you can use standard 3rd party backup software.

You can also use AWS Data Pipeline to create regular, automated copies of your file system based on a schedule that you define. For more information and to access an AWS Data Pipeline template provided by Amazon EFS, please see the Amazon EFS Walkthrough: Back Up an EFS File System.

 

Q. Is my file system accessible directly from outside my VPC?

Amazon EC2 instances within your VPC can access your file system directly, and Amazon EC2-Classic instances can mount a file system via your VPC using ClassicLink.

Q. How much data can I store?

Amazon EFS file systems can store petabytes of data. Amazon EFS file systems are elastic, and automatically grow and shrink as you add and remove files. You do not provision file system size or specify a size up front and you pay only for the storage you use.

 

Q. How many Amazon EC2 instances can connect to a file system?

Amazon EFS supports one to thousands of Amazon EC2 instances connecting to a file system concurrently.

 

Q. How many file systems can I create?

By default, you can create up to 10 file systems per AWS account per region. You can request to increase your file system limit by visiting AWS Service Limits.

 

Q. How does Amazon EFS performance compare to that of other storage solutions?

Amazon EFS file systems are distributed across an unconstrained number of storage servers, enabling file systems to grow elastically to petabyte-scale and allowing massively parallel access from Amazon EC2 instances to your data. Amazon EFS’s distributed design avoids the bottlenecks and constraints inherent to traditional file servers.

This distributed data storage design means that multi-threaded applications and applications that concurrently access data from multiple Amazon EC2 instances can drive substantial levels of aggregate throughput and IOPS. Big Data and analytics workloads, media processing workflows, content management and web serving are examples of these applications.

The table below compares high-level performance and storage characteristics for Amazon’s file and block cloud storage offerings.

Amazon EFS’s distributed nature enables high levels of availability, durability, and scalability. This distributed architecture results in a small latency overhead for each file operation. Due to this per-operation latency, overall throughput generally increases as the average I/O size increases, since the overhead is amortized over a larger amount of data. Amazon EFS's support for highly parallelized workloads (i.e. with consistent operations from multiple threads and multiple EC2 instances) enables high levels of aggregate throughput and IOPS.

Q. What’s the difference between “General Purpose” and “Max I/O” performance modes? Which one should I choose?

“General Purpose” performance mode is appropriate for most file systems, and is the mode selected by default when you create a file system. “Max I/O” performance mode is optimized for applications where tens, hundreds, or thousands of EC2 instances are accessing the file system — it scales to higher levels of aggregate throughput and operations per second with a tradeoff of slightly higher latencies for file operations. For more information, please see the documentation on File System Performance.

 

Q. How much throughput can a file system support?

The throughput available to a file system scales as a file system grows. Because file-based workloads are typically spiky – requiring high levels of throughput for periods of time and lower levels of throughput the rest of the time – Amazon EFS is designed to burst to allow high throughput levels for periods of time. All file systems deliver a consistent baseline performance of 50 MB/s per TB of storage, all file systems (regardless of size) can burst to 100 MB/s, and file systems larger than 1TB can burst to 100 MB/s per TB of storage. As you add data to your file system, the maximum throughput available to the file system scales linearly and automatically with your storage.

File system throughput is shared across all Amazon EC2 instances connected to a file system. For example, a 1TB file system that can burst to 100MB/s of throughput can drive 100MB/s from a single Amazon EC2 instance, or 10 Amazon EC2 instances can collectively drive 100MB/s. For more information, please see the documentation on File System Performance.

Q. How do I control which Amazon EC2 instances can access my file system?

When you create a file system, you create endpoints in your VPC called “mount targets.” Each mount target provides an IP address and a DNS name, and you use this IP address or DNS name in your mount command. Only resources that can access a mount target can access your file system. You can control the network traffic to and from your file system mount targets using VPC security groups.

 

Q. How do I control who can access my file system?

You can control who can administer your file system using AWS Identity and Access Management (IAM). You can control access to files and directories with POSIX-compliant user and group-level permissions.

 

Q. Does Amazon EFS provide encryption of data at rest?

Amazon EFS does not currently provide the option to encrypt data at rest, but we will offer this option soon.

Q. What interoperability and compatibility is there between existing AWS services and Amazon EFS?

Amazon EFS is integrated with a number of other AWS services, including Amazon CloudWatch, AWS CloudFormation, AWS CloudTrail, AWS IAM, and AWS Tagging services.

Amazon CloudWatch allows you to monitor file system activity using metrics. AWS CloudFormation allows you to create and manage file systems using templates.

AWS CloudTrail allows you to record all Amazon EFS API calls in log files.

AWS Identity and Access Management (IAM) allows you to control who can administer your file system. AWS Tagging services allows you to label your file systems with metadata that you define.

 

Q. What type of locking does Amazon EFS support?

Locking in Amazon EFS follows the NFSv4.1 protocol for advisory locking, and enables your applications to use both whole file and byte range locks.

 

Q. Are file system names global (like Amazon S3 bucket names)?

Every file system has an automatically generated ID number that is globally unique. You can tag your file system with a name, and these names do not need to be unique.

Q. How much does Amazon EFS cost?

With Amazon EFS, you pay only for the amount of file system storage you use per month in GB. There is no minimum fee and no set-up costs. There are no additional costs for bandwidth or requests. For Amazon EFS pricing information, please visit the pricing section on the Amazon EFS Pricing page.

 

Q. Do your prices include taxes?

Except as otherwise noted, our prices are exclusive of applicable taxes and duties, including VAT and applicable sales tax. For customers with a Japanese billing address, use of the Asia Pacific (Tokyo) Region is subject to Japanese Consumption Tax. Learn more.