• vsftpd - fstab

• https://unix.stackexchange.com/questions/67539/how-to-rsync-only-new-files
• https://stackoverflow.com/questions/15787676/rsync-how-to-do-a-checksum-on-rsync

rsync --verbose --recursive --update --ignore-existing --progress '/var/ftp/nas1/' '/var/ftp/nas2/'

--checksum