cron - running a lfpt cronjob mirror --only-missing from a seedbox, sometimes only pulls a partial file, how can i get the rest? - Ask Ubuntu

the following saved /usr/local/bin chmod 700 , ran crom /etc/crontab every 2 hours @ 37 minute mark.

#!/bin/bash login="username" pass="*****" host="seedboxurl" remote_dir='~/folder/i/want/to/copy' local_dir="/media/drivename/files" base_name="$(basename "$0")" lock_file="/tmp/$base_name.lock"  trap "rm -f $lock_file" sigint sigterm if [ -e "$lock_file" ]     echo "$base_name running already."     exit else     touch "$lock_file"     lftp -u $login,$pass $host << eof     set ftp:ssl-allow no     set mirror:use-pget-n 10     mirror -c -p10 --only-missing --log="/var/log/$base_name.log" "$remote_dir" "$local_dir"     quit eof     rm -f "$lock_file"     trap - sigint sigterm     exit fi 

this copying files/folders completed torrent folder. i'll end partial local file presume caught mid transfer download folder complete folder. question how can make lftp check local file smaller , repull/mirror if case?