If you’re not aware of Amazon EFS Service, I’d suggest you to read What is Amazon Elastic File System? before going through the FAQ.

  • Amazon EFS is a fully-managed service that makes it easy to set up and scale file storage in the Amazon Cloud. Amazon EFS file systems can automatically scale from gigabytes to petabytes of data without needing to provision storage.

  • 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.

  • 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.

  • For on-premises file systems, DataSync provides a fast and simple way to securely sync existing file systems into Amazon EFS. DataSync works over any network connection, including with AWS Direct Connect or AWS VPN. AWS Direct Connect provides a high bandwidth and lower latency dedicated network connection, over which you can mount your EFS file systems. You can also use standard Linux copy tools to move data files to Amazon EFS.

  • 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.

  • 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. Amazon EC2 instances in other VPCs can access your file system if connected using a VPC peering connection or VPC Transit Gateway. On-premises servers can mount your file systems via an AWS Direct Connect or AWS VPN connection to your VPC.

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

  • 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.

  • Provisioned Throughput enables Amazon EFS customers to provision their file system’s throughput independent of the amount of data stored, optimizing their file system throughput performance to match their application’s needs.

  • If your file system is in the provisioned mode, you can increase the provisioned throughput of your file system as often as you want. You can decrease your file system throughput in Provisioned Throughput mode or change between Provisioned Throughput and the default Bursting Throughput modes as long as it’s been more than 24 hours since the last decrease or throughput mode change.

  • 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.

  • 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.

  • AWS KMS manages the encryption keys for encrypted data at rest on EFS file systems. 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.

  • When creating a new file system in the EFS console, click “Create File System” and click the checkbox to enable encryption.

  • 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.

  • Because of the propagation delay tied to data traveling over long distances, the network latency of the network 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 network 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.

  • AWS DataSync is an online data transfer service that makes it faster and simpler to move data between on-premises storage and Amazon EFS. DataSync uses a purpose-built protocol to accelerate and secure transfer over the Internet or AWS Direct Connect, at speeds up to 10 times faster than open-source tools. Using DataSync you can perform one-time data migrations, transfer on-premises data for timely in-cloud analysis, and automate replication to AWS for data protection and recovery.

  • AWS DataSync does not support copying EFS data between AWS Regions.

  • 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.

  • Amazon EFS offers a Standard and an Infrequent Access storage class. The Standard storage class is designed for active file system workloads and you pay only for the file system storage you use per month. EFS Infrequent Access (EFS IA) is a lower cost storage class that’s cost-optimized for less frequently accessed files. Data stored on the EFS IA storage class costs less than Standard and you pay a fee each time you read from or write to a file. EFS file systems transparently serve data from both storage classes. EFS IA reduces storage costs with savings up to 85% compared to the EFS Standard storage class.

  • Moving files to EFS IA starts by creating a new file system and enabling Lifecycle Management. Lifecycle Management automatically moves your data to the EFS IA storage class after thirty days of not being accessed.

  • All Amazon EFS features are supported when using the EFS IA storage class. Files smaller than 128 KiB are not eligible for Lifecycle Management and will always be stored on EFS Standard.

  • When reading from or writing to EFS IA, your first-byte latency is higher than that of EFS Standard. EFS Standard is designed to provide single-digit latencies on average, and EFS IA is designed to provide double-digit latencies on average.

  • With Amazon EFS, you pay only for the amount of file system storage you use per month.

  • When using the Provisioned Throughput mode you pay for the throughput you provision per month. There is no minimum fee and there are no set-up charges.

Reference: Amazon EFS FAQs