You need to set up an Amazon EFS file system so that multiple EC2 instances in the same VPC but spread across several Availability Zones can access the shared storage with minimal latency. There are two EC2 instances in each Availability Zone. Which approach will provide the lowest-latency access for each instance?

Creating one EFS mount target in every Availability Zone (AZ) in the VPC, and having instances in each AZ mount the file system using the mount target in their own AZ, provides the lowest latency. EFS mount targets are AZ-specific. Mounting from a mount target in the same AZ as the EC2 instance avoids cross-AZ traffic, which inherently introduces latency. A single EFS mount target would force cross-AZ traffic for instances in other AZs. Sharing a mounted directory from one AZ to others is inefficient and not how EFS is designed to be accessed by multiple instances directly. Provisioning a separate mount target for each individual EC2 instance is unnecessary and wasteful; one mount target per AZ is sufficient for all instances in that AZ.