My colleague setup a new cacti server in a new site but on opening the graph and turning on graph debug mode it was complaining that it couldn’t find the .rrd file in /usr/share/cacti/rra/
Also importantly I noticed that the device even though successfully polling for SNMP data running a verbose query was still showing Unknown under the status column.
The issue was not the location or permissions of the rra directory but actually the location of the log directory.
There is a symbolic link /usr/share/cacti/log -> /var/log/cacti
It was this cacti directory which didn’t exist and needed creating and permissions set to 775 for cacti:apache owners.
Once changed the device is now showing up as required.