Free disk space is under the configured threshold.
From Wiki of WFilter NG Firewall
1 Reason
Free disk space is still less than the configured threshold, even after log rotating.
For example, in "Storage", it's configured as "When disk space used is more than 80%, delete history data 180 days ago". But after log rotating, disk space consumed is still more than 80%. Then you will get this message.
2 Solution
Either of below solutions can work:
- Set a less data keeping days.
- In "internet usage" module, set the recording policy to less recording.
- Add another harddisk.