[Xymon] Graph lines for disk and memory showing gaps

[Stephen Barrie]

Hello

Attached are sample memory and disk graphs. You will see the gaps in one line do not equate with the gaps in others. The gaps vary in length and there is no clear pattern. Sometimes it is for minutes but they could be for more than an hour. The output from the df command in the client still updates the server every few minutes and this never seems to miss any data. It is difficult to get the df output that coincides with gaps in the graphs as we don’t see the graphs are missing data until after the fact, but we can see that the gaps are not at the same times for all machines or all disks.

The server where we are not experiencing the problem is running 4.3.17 on Red Hat Linux. The others are 4.3.25 on Ubuntu 16.04 and 4.3.7 on Ubuntu 14.04. There are no RRD or other related errors in the logs.

A problem with the RRD parser seems a logical explanation. Is there a way of tracking what this is doing?

Stephen

From: Jeremy Laidman [mailto:jlaidman at rebel-it.com.au]
Sent: 09 August 2017 14:51
To: Stephen Barrie <sbarrie at brightsolid.com>
Cc: xymon at xymon.com
Subject: Re: [Xymon] Graph lines for disk and memory showing gaps

Can you show an example/screencap of a graph with the gaps? Do all servers and/or disks have gaps at the same time? How big are the gaps - one or two 5-minute sample size, or much larger?

The Windows disk usage message is parsed by different code to that which parses the UNIX and Linux "df" output. That might have something to do with it.

Is 4.3.25 in use on all Xymon servers?

Check the Xymon logs for error messages. Perhaps the RRD parser is crashing.

It's possible that the "df" output is sometimes not parseable by the RRD parser, and so the data is ignored. Can you show the [df] section from the client data during one of the gaps, and at another time when there are no gaps?

J


On 9 August 2017 at 22:13, Stephen Barrie <sbarrie at brightsolid.com<mailto:sbarrie at brightsolid.com>> wrote:
Hi

We have a few Xymon servers running on Ubuntu 14.04 and 16.04 that show gaps in the graphs for disk and memory metrics. This specifically relates to Linux and Unix clients reporting to these servers. The graph lines for Windows clients look ok.

If the same Unix and Linux clients are pointed to another server running Red Hat we do not see the same gaps in the graphs. Upgrading the client version does not resolve this. So it seems there is a problem with graph data being created on the Xymon server on Ubuntu. We are using the package version 4.3.25. Is there a known issue with this?

Regards

Stephen Barrie
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