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 and the file system’s DNS name. 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 Linux-based AMIs for Amazon EC2. 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?

You can load data into an Amazon EFS file system from your Amazon EC2 instances or from your on-premises datacenter servers.

Amazon EFS file systems can be 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).

Amazon EFS file systems can also be mounted on an on-premises server, so any data that is accessible to an on-premises server can be read and written to Amazon EFS using standard Linux tools. For more information about accessing a file system from an on-premises server, please see the On-premises Access section of this FAQ.

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.

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. How do I access my file system from outside my VPC?

Amazon EC2 instances within your VPC can access your file system directly, and Amazon EC2 Classic instances outside your VPC can mount a file system via ClassicLink. On-premises servers can mount your file systems via an AWS Direct Connect connection to your VPC.


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

Amazon EBS
PIOPS

Per-operation latency

Low, consistent

Lowest, consistent

Throughput scale

Multiple GBs per second

Single GB per second

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.” When mounting from an EC2 instance, your file system’s DNS name, which you provide in your mount command, resolves to a mount target’s IP address. 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: What is Amazon EFS Encryption?

Amazon EFS seamlessly offers encryption of EFS file systems. Data is transparently encrypted while being written, and transparently decrypted while being read, so you don’t have to modify your applications. Encryption keys are managed by the AWS Key Management Service (KMS), eliminating the need to build and maintain a secure key management infrastructure.

 

Q: What is the AWS Key Management Service (KMS)?

AWS KMS is a managed service that makes it easy for you to create and control the encryption keys used to encrypt your data. AWS Key Management Service is integrated with AWS services including Amazon EFS, Amazon EBS, and Amazon S3, to make it simple to encrypt your data with encryption keys that you manage. AWS Key Management Service is also integrated with AWS CloudTrail to provide you with logs of all key usage to help meet your regulatory and compliance needs. To learn more about KMS, visit the AWS Key Management Service product page.

 

Q: How do I enable encryption for my Amazon EFS file system?

You can enable encryption for your EFS file system in the EFS console, or by using the AWS CLI or SDKs. When creating a new file system in the EFS console, click “Create File System” and click the checkbox to enable encryption. For more details, see the user documentation on Encryption.

 

Q: Does encryption impact Amazon EFS performance?

Encrypting your data has a minimal effect on I/O latency and throughput.


Q. How do I access an EFS file system from servers in my on-premises datacenter?

To access EFS file systems from on-premises, you must have an AWS Direct Connect connection between your on-premises datacenter and your Amazon VPC. AWS Direct Connect establishes a private network connection between your on-premises datacenter and AWS. If you do not already have an AWS Direct Connect connection, you can create one by following the instructions in the AWS Direct Connect user guide.

You mount an EFS file system on your on-premises Linux server using the standard Linux mount command for mounting a file system via the NFSv4.1 protocol.

For more information about accessing EFS file systems from on-premises servers via AWS Direct Connect, please see the documentation.

 

Q. What can I do by enabling access to my EFS file systems from my on-premises servers?

You can mount your Amazon EFS file systems on your on-premises servers, and move file data to and from Amazon EFS using standard Linux tools and scripts. The ability to move file data to and from Amazon EFS file systems enables three use cases.

First, you can migrate data from on-premises datacenters to permanently reside in Amazon EFS file systems.

Second, you can support cloud bursting workloads to offload your application processing to the cloud. You can move data from your on-premises servers into your EFS file systems, analyze it on a cluster of EC2 instances in your Amazon VPC, and store the results permanently in your EFS file systems or move the results back to your on-premises servers.

Third, you can periodically copy your on-premises file data to EFS to support backup and disaster recovery scenarios.

 

Q. Can I use an AWS VPN to access an EFS file system from on-premises?

No, Amazon EFS does not support access over AWS VPN.

 

Q. Can I access my Amazon EFS file system concurrently from my on-premises datacenter servers as well as Amazon EC2 instances?

Yes, you can access your Amazon EFS file system concurrently from servers in your on-premises datacenter as well as Amazon EC2 instances in your Amazon VPC. Amazon EFS provides the same file system access semantics, such as strong data consistency and file locking, across all EC2 instances and on-premises servers accessing a file system.

 

Q. What is the recommended best practice when moving file data to and from on-premises servers via AWS Direct Connect?

Because of the propagation delay tied to data traveling over long distances, the network latency of a Direct Connect connection between your on-premises datacenter and your Amazon VPC can be tens of milliseconds. If your file operations are serialized, the latency of the Direct Connect connection directly impacts your read and write throughput; in essence, the volume of data you can read or write during a period of time is bounded by the amount of time it takes for each read and write operation to complete. To maximize your throughput, parallelize your file operations so that multiple reads and writes are processed by EFS concurrently. Standard tools like GNU parallel enable you to parallelize the copying of file data. For more information, see the online documentation.


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 AWS services is subject to Japanese Consumption Tax. Learn more.