Recently I wanted to copy a load of files from a server to a Synology NAS. 

You can use Synology GUI to map a remote file using SMB with a username and password. You can then reference that folder for an RSYNC copy to do the inital sync then copy changes 

The RSYNC Command is below

rsync –archive –progress –verbose –inplace –exclude ‘*@SynoResource’ –exclude ‘@eaDir’ –exclude ‘*.vsmeta’ –exclude ‘.DS_Store’ ‘/volume1/Remote/Dir/’ ‘/volume1/Dir/’ >> /volume1/DIR/log1.txt 2>&1

Just to show you –Archive is equals -rlptgoD (no -H,-A,-X)  , so it will overwrite newer files with the older ones so only use the above for the initial sync

To replicate the rest when the new volume is being used do

rsync -rlptgoDu –progress –verbose –inplace –exclude ‘*@SynoResource’ –exclude ‘@eaDir’ –exclude ‘*.vsmeta’ –exclude ‘.DS_Store’ ‘/volume1/Remote/Dir/’ ‘/volume1/Dir/’ >> /volume1/DIR/log1.txt 2>&1