Opened at 2011-01-26T18:46:22+01:00
Closed at 2012-02-29T10:55:36+01:00
#1023 closed defect (wontfix)
Derive of Epoch
Reported by: | fgm | Owned by: | nobody |
---|---|---|---|
Priority: | low | Milestone: | Munin 1.4.7 |
Component: | plugins | Version: | 1.4.4 |
Severity: | minor | Keywords: | |
Cc: |
Description
A very simple plugin plotting time() since the Epoch as a counter should return a
straight horizontal line at 1 second per second, and that is mostly the case. However, several times a day, the value drops slightly below 1, and the daily average can be below 0.997
#!/bin/sh case $1 in config) cat << EOT graph_title Date as seconds graph_vlabel seconds per second graph_info The number of seconds since the last measurement. Should be a continuous line. graph_category osinet date.info Info about date seconds date.label seconds date.type COUNTER date.max 1.01 date.min 0.99 EOT exit 0;; esac echo -n "date.value " date +%s
Change History (2)
comment:1 Changed at 2012-02-05T16:11:22+01:00 by cbiedl
comment:2 Changed at 2012-02-29T10:55:36+01:00 by kenyon
- Resolution set to wontfix
- Status changed from new to closed
Thanks for the report and explanation. I have linked to this ticket from the faq.
It seems that there is nothing for munin to do here, so I will close this ticket.
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Seems you got bitten by two effects. But at first, a workaround: Prefix the value with a time stamp, like in
Regarding your report, the first thing is rrdtool does interpolation. So, if the interval between data fetches is not exactly every 300 seconds, but 299 or 301 instead, rrdupdate will take this into accout. The 0.997 values you see are just the result of 299/300.
The second question is: If the long-time average no doubt is just 1, why don't you see 1.003 in the maximum value? Well, that's rounding in the presentation. The rrd has the values, they are not shown in that precision.
To check, graph the double and half values of the current time:
This yields for me:
Regards,