PPPOE period WAN reset ends in 109% filled Disc

[KHEins]

Hey,

i have a very strange Problem with my new installed Opnsense.
I have a 2 WAN Setting one VDSL with PPPOE and one LTE as Backup line.
Because of a 24h reset of the Line i wanted to let this happend in the night and not in the time when i am in Zoom Meetings for work. So i found out that the easyest way is to configure a Cron Job that periodically reset the wan interface. I configured it and it work but bring the System disc to a 109% fill and because of that all Service died. I found out that Suricata Log and flow.log filled disc with large Files.
When i move the time of the Cron Job to another time Opnsense will "die" on that time.
any suggestions what i can do?