It might be a noob question but couldn't find anything solid on the web so here I go.
I know that both EBS (Elastic Block Store) and EFS (Elastic File System) communicate with EC2 over the network (data transmission). To make an EFS work with EC2, I read that traffic on the NFS port must be allowed by the inbound security group (attached to EC2 instance).
But, I don't think any such configuration is required for EBS. So, why we don't need any configuration for EBS and yet it works?
Amazon EBS volumes attach to Amazon EC2 instances as devices via a separate network connection to the host computer. It does not attach via a VPC, so Security Groups are not available.
Amazon EBS volumes are bandwidth restrictions on Amazon EBS volumes, which vary by Volume Type. See: Amazon EBS volume types - Amazon Elastic Compute Cloud
Older Amazon EC2 instance types could increase bandwidth to EBS volumes by using Amazon EBS Optimization that uses "an optimized configuration stack and provides additional, dedicated capacity for Amazon EBS I/O". Modern EC2 instances have this enabled by default.
In contrast, Amazon EFS is attached to instances via a VPC, so Security Group rules apply.
