munin-update is the primary Munin component. This script is responsible for contacting all the agents (munin-nodes) and collecting their data. Upon fetching the data, munin-update stores everything in RRD files - one RRD files for each field in each plugin.

Running munin-update with the --debug flag will often give plenty of hints on what might be wrong.

munin-update is a component in the Munin server.