These days the traffic that we have to monitor is huge so maybe keeping logs forever is not something that can be achieved. In order to configure how many days will the logs be stored, before Zeek wipe out them, follow these steps.

Edit /opt/zeek/zeekctl.cfg

LogExpireInterval = 10 day

Until now there is not an automated way to achieve it, so you have to edit the crontab file.

crontab -e

*/5 * * * * /opt/zeek/bin/zeekctl cron

Check if Zeek Cron Jobs are enabled

zeekctl cron ?

If it is disabled, then run the following command in your terminal.

zeekctl cron enable