Hello people,
I would like to know how to make a report with a graph of the states of a hostgroup of the hosts in a down state with the operational time (hours or minutes) 7
I believe you should be able to make the kind of report you are looking for using the State History Report. You can find this in Reports>Available Reports>State History, and then change the "Limit To" option to the hostgroup you are looking for, and the State to Critical. If you click the "Add to My Reports" button the current state of this report can be saved to "My Reports"
Unfortunately there isn't a way to get the specific graph visualization you are looking for on this report currently.