Elastic File System

# Elastic File System

What is Elastic File System (EFS)?¶

• Managed NFS volumes that can be mounted on many EC2 instances, across many AZs.
• Very expensive.
• Pay based on what is used (automatic scaling).
• Highly available.
• Good for content management, web serving, data sharind, wordpress.
• Uses NFSv4.1.
• Uses security groups to control access.
• Only compatible with linux.
• Can use lifecycle management to remove files after a number of days.
• Throughput mode has two options
• Bursting
• Provisioned
• Performance mode has two options
• General purpose
• Max I/O
• Can have a public or private IP.
• Two modes
• Standard: Frequently accessed files.
• Infrequent Access (EFS-IA): cheaper to store files, but additional cost to retrieve files.

Mounting EFS volumes¶

• Need to install the amazon-efs-utils package or nfs-utils.
• Mounting using efs helper, or nfs client.
• Make sure security group allows NFS port 2049.

Cleaning up EFS¶

• Make sure volumes are removed after deleting EFS volume.
• Make sure security group(s) are cleaned up.

EBS vs EFS¶

• EBS can only be attached to one instance at a time. EFS can attach to multiple instances.
• EBS is bound to a specific AZ, EFS is multi-AZ.
• EFS only for linux (NFS).
• EFS is more expensive than EBS.
• Can use EFS-IA to save money via lifecycle policy.
• EFS billed for what you use. EBS you pay for provisioned capacity.
• gp2 IO increases if the disk size increases.
• io1 can increase IO independantly of disk size.
• To migrate EBS volume across AZ, take a snapshot, and restore into the new AZ. Uses alot of IO.
• EBS will be terminated by default when the instance is terminated (can be turned off).

Encryption¶

• Encryption at rest using KMS keys.

Scaling¶

• Supports thousands of concurrent clients.
• Upto 10GB/sec throughput.
• Can grow to PB scale file systems.
• Performance mode is set at creation time.

Performance Mode¶

General Purpose (default)¶

• Use for latency sensitive use cases (web servers etc).

Max I/O¶

• Higher latency.
• Use for highly parallel workloads (big data, media processing).

Throughput Mode¶

Bursting¶

• 50MB/sec per TB, up to 100MB/sec bursts.

Provisioned¶

• Define throughput seperately from storage size.
• Max 1GB/sec throughput.

Storage Tiers¶