We made a check that counts active users.
The data returned from the chack seems to be correct. When I am on the Service State Information page I can follow the performance data returned.
It has the following layout : users=144;0;300
Looking into the /usr/local/nagios/var/rrd/<machine-name>/<check-name>/users directory, I see three files : thresholds.rrd, uom (empty), and value.rrd.
We basically copied the performance data creation syntax from another check, and this one works. Although data is present, and performance data can be
seen on the Service State page, no graph is being created for the active users check.
I'm not sure if you guys need more information. If you do, please let me know. We would be grateful if this enigma could be solved.