Performance Graphs Showing Data during Host Down Time Periods
Why are performance graphs displaying data during periods when the host was down?
The data that makes up the graphs are stored in rrd files found under /usr/local/nagios/share/perfdata/<hostname>/. These files also hold information about how the data is stored and ultimately displayed, including the heartbeat setting "minimal_heartbeat" which by default holds the value 8460(seconds). If a host or service becomes unavailable for a period that does not exceed the heartbeat limit then a value is calculated for the time intervals that went missing. If the heartbeat value is exceeded, then no values will be stored and the graph will be blank for that time period.
Viewing the Heartbeat Value
To see the values and change them we can use the rrdtool command. For example:
rrdtool dump /usr/local/nagios/share/perfdata/localhost/PING.rrd | more
Changing the Heartbeat Value
To change the heartbeat on the above you would run:
rrdtool tune --heartbeat 1:60
Another option would be to modify /usr/local/nagios/etc/pnp/process_perfdata.cfg which includes this line:
|Posted by: rspielman - Tue, Dec 7, 2021 at 9:12 AM. This article has been viewed 1209 times.|
|Online URL: https://support.nagios.com/kb/article/performance-graphs-showing-data-during-host-down-time-periods-914.html|
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