AWS DataSync is a service designed to move, migrate, and synchronize data from on-prem to EFS ( or other Storage Services)
Examples of use cases:
migrate an NFS file system from EC2 to EFS within same region.
replicate an NFS file system from EC2 in a region to a EFS in another region for disaster recovery
migrate an Amazon EFS file system to another EFS with different configurations ( like lifecycle management, or performance mode)
replicate an EFS file system to another region for disaster recovery