If you need something as a canned report - leverage "360 Protection
Report" in FAZ. We have charts around 'Disk Utilization for Fortigates"
etc. that you are asking for. As customers have one of the SNMP servers
like Nagios etc. We also provide tons ...
Hi Per - We have event logs that the FortiAnalyzer generates to enable
this for you. Please try System Settings > Event Log to look at specific
events with Sub Type = diskquota. That should enable to see all the
events around the disk usage over time...