[rrd-users] gap in graph in case of UNKNOWN value
m4rtntns at gmail.com
Fri Jun 10 00:17:54 CEST 2011
I'm sure it's showing zeros- when the network outage started, HDD
temperature value went from previous value directly to zero. If I had
a network outage and server was unreachable to a machine where
rrdtools runs, following data was written to RRD:
# rrdtool fetch HDD.rrd AVERAGE -s 1307061000 -e 1307075400
1307061600 is just before the outage and outage was over since
1307074800. RRD was made with a following command:
rrdtool create HDD.rrd \
--step '60' \
If any additional information is needed, please ask!
Am I correct, that in my case there are zeros written to the RRD in
case of UNKNOWN value? If yes, how to change this behavior?
2011/6/7 Simon Hobson <linux at thehobsons.co.uk>:
> Martin T wrote:
>>I have a RRD database with a step of 60s and heartbeat of 120s. This
>>database holds the GAUGE value(HDD temperature of my server). There is
>>a script which asks temperature value from the server after every 60s
>>and updates the database file. Finally I have a "rrdtool graph"
>>script, which draws the graph. Problem is that in case the server is
>>not reachable to the machine where rrdtool runs and UNKNOWN value is
>>written to the RRD database, there is no blank gap on the graph.
>>Instead it looks like the temperature value is assumed to be "0". What
>>might cause this?
> How are you graphing (ie what is the graph command) ?
> Are you sure it's showing zero and not a gap ?
> Are you sure you are writing unknowns and not zeroes to the database
> OR are not writing anything ?
> With the values given, after 2 minutes you should see unknown in the
> database PROVIDED you are either not writing data, or are writing
> "unknown" as the value.
> Simon Hobson
> Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
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