For a particular time frame, it is confirmed that agent collections were not running and metrics are not available; the following behavior is noticed when Foglight database reports are generated:
The Disk Space Usage report (Disk Capacity) will always display values for the selected time frame; if those values are not available it will display "0.00".
Both reports should display the message "There Is No Data To Display" when metrics are not present for the selected time frame.
Please contact Quest Support if assistance is needed for this issue.
Waiting for fix in a future release of the Foglight cartridge for SQL Server (SSFOG-667).