Ubiquiti Unifi – eating all disk space

What should you do when Ubiquiti Unifi is eating all of the disk space?

Webinterface -> Settings -> Maintenance -> Historical Data Retention -> 90 days -> apply

-> compact database

Further reading:

https://community.ui.com/questions/UNIFI-Eating-all-disk-space-or-Mongodb/0d35538e-16e9-45d4-a1e4-c1d8a4c0fc65

https://community.ui.com/questions/Unifi-Controller-5-4-11-on-Ubuntu-Eats-All-Disk-Space/f15b3db7-4e72-455e-8070-1585a91591e8