Syntax:

rsync -ave ssh user@server:source destination

Example:

 rsync -ave ssh user@server:/home/steviewdr/public_html /home/steviewdr/
#or
 rsync -ave "ssh -p 2222" /home/user/folder/ username@remotedestinationserver:/home/user/folder/

Recently migrating a MySQL Server. We had a new one setup. There was ~8GB of data in /var/lib/mysql needing to be sync'd.

Option A: shutdown mysql and copy across /var/lib/mysql Option B: Use rsync to sync the data. That way, downtime would only take 1-2 minutes (to resync latest modified files etc.

 #ssh into current mysql server, and run:
 rsync -avPin --delete /var/lib/mysql newhost:/var/lib/
 
 a = archive (equals -rlptgoD  for recursive, group, owner, permissions etc.)
 v = verbose
 P = progress
 i = itemise changes
 n = dry run (remove the n, for the proper run)
 --delete = delete files on target, which were deleted on host since last run.

After than runs. Stop MySQLd on current server, and run the same rsync again.