Uncontrolled filling of logfiles

  1. You could tweak your logrotate settings to rotate more often and delete files older than specified amount of days…
    Have a look at /etc/logrotate.conf and /etc/logrotate.d/rsyslog

  2. You could also modify the service file

/etc/systemd/system/qmi_reconnect.service

And send standard error and/or standard output to where nobody cares about it:

StandardOutput=null
StandardError=null

The spamming probably comes from StandardError so just sending that to null might suffice.

Note: make sure you do a…

systemctl daemon-reload

After you have modified service files.