Rsync tricks
Sync list of files
$ cat /root/files.txt
/home/user/backup1.tgz
/home/user/backup2.tgz
rsync -a --append --partial --progress -e 'ssh -p 2222' --files-from=/root/files.txt / [email protected]:/volume1/user/
Exclude source sub-folders
Alternative tools: rclone