[Xymon] Gaps in graphs

[Carl Melgaard]

On Sat, 6 Mar 2021 at 02:04, Scot Kreienkamp <Scot.Kreienkamp at la-z-boy.com<mailto:Scot.Kreienkamp at la-z-boy.com>> wrote:
2021-03-03 01:24:19.002264 xxx/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614731059, different data

That usually happens because graphs by default store data once every 5 minutes.  However, if it receives data more often, say every minute, then it can’t store that in the RRD because it can only store one data point every 5 minutes.  Since it’s receiving data more often than once in the 5 minute window the RRD backend triggers that message.

>Are you receiving these "duplicate RRD data" messages every 5 minutes, or only occasionally (such as when you're seeing gaps in your graphs)?
>It might be helpful to see one of your graphs with gaps in it.
>Also, can you provide maybe 10 sequential log messages with the "duplicate RRD data" in them? I'd like to get a sense of their regularity and frequency.

2021-03-03 01:24:19.002264 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614731059, different data
2021-03-03 02:55:15.002852 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614736515, different data
2021-03-04 10:01:17.004140 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614848477, different data
2021-03-05 14:15:25.007389 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614950125, different data
2021-03-05 14:15:25.007523 x/ifstat.eno16780032.rrd: Bug - duplicate RRD data with same timestamp 1614950125, different data
2021-03-05 22:56:18.014486 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1614981378, different data
2021-03-05 22:56:18.015006 x/ifstat.eno16780032.rrd: Bug - duplicate RRD data with same timestamp 1614981378, different data
2021-03-06 12:30:28.002023 x/netstat.rrd: Bug - duplicate RRD data with same timestamp 1615030228, different data
2021-03-06 12:30:28.002952 x/ifstat.eno16780032.rrd: Bug - duplicate RRD data with same timestamp 1615030228, different data

>One last thing to look at. Are the gaps actual missing data points, or are they values of zero? The way to tell this is to dump the RRD file's contents using something like "rrdtool fetch netstat.rrd AVERAGE | tail -100" (or "less rather than tail -100) and look for either zero or low numbers, >or NaN (not a number) entries. [Note that the last few are usually NaN because they're still waiting for updates, so you can ignore those.]

Currently I cant actually find a graph with a gap in it. I just noticed because it happened on the Xymon server itself. On my old setup, it never happened.

Also in xymonclient.log I get these quite alot, dunno if its related:

mv: cannot stat '/dev/shm/logfetch.x.cfg.tmp': No such file or directory
cat: /dev/shm/xymon_vmstat.x: No such file or directory
cat: /dev/shm/xymon_vmstat.x: No such file or directory

Regards,

Carl
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