The difference between EBS and EFS.
EBS volumes are only available in one Availability Zone and can be attached to only one ec2 instance at any one time.
Remember when taking a backup of your EBS volume that you should not perform a backup while your ec2 instance is handling traffic.
By default the EBS root volume will be terminated when the ec2 instance gets terminated although you’re able to override this setting via the management console.
EFS Elastic File System is able to be mounted across hundreds of ec2 instances across multiple Availability Zones and can be used to share files across multiple ec2 instances.
EFS is only available for Linux ec2 instances and is about three times more expensive than an EBS volume.
EFS supports storage tiers meaning you have the ability to move files to a different storage tier after a specified number of days which will enable some cost savings.
With EBS you have to provision the size of the volume when it is created where as for EFS you are only billed for what you use.
In summary EFS is a file system which is able to be used across many ec2 instances and across many Availability Zones where as an EBS is only available in one Availability Zone and attached to one ec2 instance