Which solution will meet these requirements with the LEAST operational overhead?
Use AWS DataSync.
Use AWS Snowball devices.
Set up an SFTP server on Amazon EC2.
Use AWS Database Migration Service (AWS DMS).
Explanations:
AWS DataSync is designed for automated, scheduled, and managed transfers between NFS file systems across AWS Regions, minimizing operational overhead.
AWS Snowball is primarily for offline data transfer, ideal for large initial migrations or migrations with no regular schedule; it has high operational overhead for periodic transfers.
Setting up an SFTP server on EC2 requires manual management of the server, data scheduling, and security, which increases operational overhead for periodic transfers.
AWS Database Migration Service (DMS) is intended for database migrations, not for file system data transfer, and is not suitable for NFS file system transfers.
I infer that the answer is:
Use AWS DataSync.