• Adding a new datasource to an RRD database
  After upgrading several servers with a newer instance of nsclient++, we discovered Memory graphs were broken because of new performance metrics included in the check memory results. Well broken is subjective, the new performance data included the percentage free (as before), with the addition of the actual physical value (ie 1GB). This addition was missing from the RRDs when they were originally created, so when pnp4Nagios was updating the XML file it uses, it said it had 2 data sets, but the RRD only had one. Here’s how I fixed the issue.
  in Computers > Linux with datasources rrd rrdtool tool utility
• cacti
  Frontend to RRDTool, sets up datasources, gathers data and displays graphs
  in Computers > Linux with computers datasources displays frontend gathers graphs linux rrdtool

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