A combined graph overlays several graphs in the same graph which will give a better overview of how two different checks are performing.
It takes one or more service from one or more host and lays them on top of each other in the same graph.
The service checks must have the same name on all the hosts for combined graphs to work.
The combined graphs is created though the configuration.
Go to Configure in the menu.
Click on Combined Graphs
Enter a name of the combined graph and click on Add
Select the service to graph and from which hosts this service should be fetched from. Also add a name and comment.
Click on Submit.