Rsync with resume

#!/bin/bash

while [ 1 ]
do
    rsync -avrvv --size-only --partial --progress user@host:/path_on_server localpath
    if [ "$?" = "0" ] ; then
        echo "rsync finished"
        exit
    else
        echo "Rsync problem, retrying in 3 minutes"
        sleep 180
    fi
done