It seems that my logs are filling up the tempfs quite often, and to my understanding, it should be saved to my zfs pool instead of an tmpfs?
ilesystem Size Used Avail Capacity Mounted on
zroot/ROOT/default 194G 19G 175G 10% /
devfs 1.0K 1.0K 0B 100% /dev
/dev/gpt/efiboot0 260M 1.8M 258M 1% /boot/efi
zroot 175G 96K 175G 0% /zroot
zroot/tmp 175G 2.1M 175G 0% /tmp
zroot/var/mail 175G 136K 175G 0% /var/mail
zroot/var/crash 175G 104K 175G 0% /var/crash
zroot/usr/ports 177G 1.6G 175G 1% /usr/ports
zroot/usr/home 175G 96K 175G 0% /usr/home
zroot/jails 175G 120K 175G 0% /jails
zroot/var/tmp 175G 200K 175G 0% /var/tmp
zroot/var/log 176G 1.1G 175G 1% /var/log
zroot/usr/src 176G 559M 175G 0% /usr/src
zroot/var/audit 175G 96K 175G 0% /var/audit
zroot/vms 183G 7.7G 175G 4% /zroot/vms
zroot/jails/containers 175G 104K 175G 0% /jails/containers
zroot/jails/templates 175G 104K 175G 0% /jails/templates
zroot/jails/media 175G 191M 175G 0% /jails/media
zroot/vms/podman 175G 132K 175G 0% /zroot/vms/podman
zroot/jails/templates/13.2-RELEASE 176G 550M 175G 0% /jails/templates/13.2-RELEASE
zroot/jails/containers/dnsdist 176G 978M 175G 1% /jails/containers/dnsdist
zroot/jails/containers/bind 176G 638M 175G 0% /jails/containers/bind
zroot/jails/containers/unifi 177G 2.0G 175G 1% /jails/containers/unifi
zroot/jails/templates/13.2-RELEASE-skeleton 175G 104K 175G 0% /jails/templates/13.2-RELEASE-skeleton
tmpfs 3.2G 76M 3.1G 2% /var/log
devfs 1.0K 1.0K 0B 100% /var/dhcpd/dev
devfs 1.0K 1.0K 0B 100% /var/captiveportal/zone0/dev
zroot/vms/FedoraIoT 175G 120K 175G 0% /zroot/vms/FedoraIoT
System > Settings > Miscellaneous > Disk / Memory Settings
Thanks, that was it.
However after disabling it, I had to manually stop syslog-ng and only after I was able to unmount the tmpfs.
I would have just rebooted.