Hello Morten,

thank you very much for your help.

Picture e7: graphite-carbon 0.9.15-1, nav 4.8.2-1stretch (debian stretch)
Picture jy: graphite-carbon 0.9.15-1, nav 4.8.2-2stretch (debian stretch)

We don't have any SNMP timeouts in our logs, ipdevpoll reports no errors and strangely enough this issue affects only some interfaces:
*On one device we have an AE consisting of 4 interfaces and all 4 interfaces have graphs without gaps, but the AE interface consists of mostly gaps. The problems are not limited to AE interfaces though, that would be too easy.
*On another device we have interfaces with 1000BASE-T (=copper) and some of them have no gaps at all while others are mostly gaps.

Best regards
Karl



From: Morten Brekkevold [mailto:morten.brekkevold@uninett.no]
Sent: Monday, Feb 19, 2018 11:36 AM CET
To: Karl Gerhard
Cc: nav-users@uninett.no
Subject: Is that a healthy carbon cache?

On Fri, 16 Feb 2018 17:13:08 +0100 Karl Gerhard <karl_gerh@gmx.at> wrote:


Hello,

we're having problems with gaps in graphs (only for some interfaces) and I'm
working through the https://nav.uninett.no/doc/4.8/faq/graph_gaps.html
guide. I've arrived at the part with the "Carbon Cache" and I'd like to know
whether those two graphs represent a healthy state:
http://abload.de/img/e7zassl.png
http://abload.de/img/jyz3sjf.png

This does not look like a cache that is being saturated, so if there's a
problem, it's likely somewhere else. But, however, as you noted, it is a
bit disconcerting that a negative number of cache entries are reported
(which would be impossible).

Which version of carbon are you on?