moving large amount of data with rsync via ssh session

I am trying to think of the best way to move a large amount of data.

I have about 4 TB of data that I need to copy between two Debian machines (both headless) that are in my house. I have them both connected to the same network via gigabit switch.

I was going to ssh into one of the Debian machines from my desktop computer and then just use the rsync command to copy all the files over. If I do this, do I need to leave the ssh session and terminal open on my desktop? Or is there is a way to do this via rsync that will allow me to close out the session? Also of course welcome to take suggestions of easiest way to move large amounts of data.