rsync -aP source/ target/
if you meet some performance issue during ext4 to nfs mounted to local filesystem, try below command replace rsync
1. ssh-copy-id user@x.x.x.x
2. find folder/ -mindepth 1 -maxdepth 4 -type d -exec bash -c ‘tar cz {} | ssh user@x.x.x.x tar -xzf – -C backup’ \;