Found! It was in /etc/crontab.
Hi, I have configured this script more than 10 years ago, and of course I don't remember anything. It is not in the cron, and i can't find a way to stop it from execution every night. These are all files I have found with locate \automysqlbackup /etc/automysqlbackup /etc/automysqlbackup/LICENSE /etc/automysqlbackup/README /etc/automysqlbackup/automysqlbackup.conf /etc/automysqlbackup/myserver.conf /home/username/automysqlbackup-v3.0_rc6.tar.gz /home/username/automysqlbackup /home/username/automysqlbackup.conf...