[rrd-users] Large-interval data is not displaying as I expected
herminio at gmail.com
Sun Feb 22 04:17:15 CET 2009
I'm quite new to rrdtool, though have managed to set up a number or
useful graphs, thanks to the excellent documentation out there.
But this time I am stumped. I want to produce a chart showing how many
hosts have been added to a deny-list by DenyHosts. The data comes from
simply counting the lines in a continuously growing text file of IP
This is how I created the rrd database:
rrdtool create denyhosts.rrd --step 86400 \
The step size of 86400 is one day.
This is my update script:
HOSTCOUNT=`wc -l < /etc/hosts.deniedssh`
/usr/local/bin/rrdupdate ~/rrd/denyhosts.rrd N:`echo $HOSTCOUNT`
I run the update at one minute past midnight ever day.
After a few days of this I fetched some data.
>rrdtool fetch denyhosts.rrd LAST --end now --start now-5d
It is not what I expected.
2.314e-05 multiplied by 86400 is close enough to 2, which is correct.
But 1.5906e-05 multiplied by 86400 is 1.374... which doesn't make any
sense. It should be 2 again for that day.
Plotting the results confirms the fetched data:
Only some of the data points line up with 1.0, 2.0, 3.0 integer boundaries.
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