[mrtg] Re: Spike after rebooting routers

[Michael Markstaller]

The last answers on the list led me to think it's "by design", if it isn't I'd be even happier to help fix the issue, if somebody gives me some directions what to look for ..
I have gone deeper into this now and it's reproducible on one box with at least some counters; At least something goes completely wrong, but I don't know with which logic MRTG "notices" a buffer overflow ( somebody can tell me ?), maybe then I can track this down further.
Again, just to make sure, I fully understood that I can limit the spikes with MaxBytes or AbsMax but this doesn't solve the problem.

MRTG 2.9.29 / RRDtool 1.0.41

RRDtool dump from the affected DS:
--- cut ---
...
<!-- 2003-05-09 20:55:00 CEST / 1052506500 --> <row><v> 1.6371118494e-01 </v><v> 2.6358050941e-01 </v></row>
<!-- 2003-05-09 21:00:00 CEST / 1052506800 --> <row><v> 8.6853772705e+06 </v><v> 8.6853767942e+06 </v></row>
<!-- 2003-05-09 21:05:00 CEST / 1052507100 --> <row><v> 5.6311787342e+06 </v><v> 5.6311784606e+06 </v></row>
...
--- cut ---

Values in MRTG display:
--- cut ---
Max  ifInUcast:   8685.4 kpkts/s  Average  ifInUcast:   79.5 kpkts/s  Current  ifInUcast:   0.2 pkts/s 
Max  IfOutUcast:   8685.4 kpkts/s  Average  IfOutUcast:   79.5 kpkts/s  Current  IfOutUcast:   0.3 pkts/s 
--- cut ---


MRTG config of target:
--- cut ---
# ---------------------------------------------------------------------
Target[ROUTER_4-UCastpkts]: ifInUcastPkts.4&ifOutUcastPkts.4:COMMUNITY at ROUTER:
Directory[ROUTER_4-UCastpkts]: ROUTER/detail
YLegend[ROUTER_4-UCastpkts]: pkts/s
ShortLegend[ROUTER_4-UCastpkts]: pkts/s
Legend1[ROUTER_4-UCastpkts]: Avg Input Unicast Packets
Legend2[ROUTER_4-UCastpkts]: Avg Output Unicast Packets
Legend3[ROUTER_4-UCastpkts]: Max Input Unicast Packets
Legend4[ROUTER_4-UCastpkts]: Max Output Unicast Packets
LegendI[ROUTER_4-UCastpkts]: &nbsp;ifInUcast:&nbsp;
LegendO[ROUTER_4-UCastpkts]: &nbsp;IfOutUcast:&nbsp;
MaxBytes[ROUTER_4-UCastpkts]: 100000000
Options[ROUTER_4-UCastpkts]: growright, nopercent
Title[ROUTER_4-UCastpkts]: Et0 Unicast Packets -- 04214
PageTop[ROUTER_4-UCastpkts]: <H1>Ethernet0 Unicast Packets -- 04214</H1>
...
--- cut ---

MRTG debug before reload:
--- cut ---
...
2003-05-09 20:57:38 -- --base: Act on Router/Target ROUTER_4-ucastpkts
2003-05-09 20:57:38 -- --base: Get Current values: 593, 859, undef, undef, 1052506618)
2003-05-09 20:57:38 -- --base: Create Graphics
2003-05-09 20:57:38 -- --base: start RRDtool section
2003-05-09 20:57:38 -- --base: maxi:100000000, maxo:100000000
2003-05-09 20:57:38 -- --base: Check for Thresholds
...
MRTG debug after reload, next mrtg round:
--- cut ---
2003-05-09 21:02:40 -- --base: Act on Router/Target ROUTER_4-ucastpkts
2003-05-09 21:02:40 -- --base: Get Current values: 48, 59, undef, undef, 1052506918)
2003-05-09 21:02:40 -- --base: Create Graphics
2003-05-09 21:02:40 -- --base: start RRDtool section
2003-05-09 21:02:40 -- --base: maxi:100000000, maxo:100000000
2003-05-09 21:02:40 -- --base: Check for Thresholds
--- cut ---

results in the values above.


Michael

-----Original Message-----
From: Woodcock, Bradford [mailto:Bradford.Woodcock at Level3.com]
Sent: Friday, May 09, 2003 7:50 PM
To: Michael Markstaller; MRTG Mailing List
Subject: RE: [mrtg] Re: Spike after rebooting routers


Not sure if my spikes were comparable to yours. However I got spikes on
version 2.9.17 . Upgraded to 2.9.22 and they are gone (this is also with
rrdtool/14all which may have come into play). I'm surprised to see you
have issue with an even newer version. It could be due to a different
reason for causing the spike (where this downgrade may not help) or a
reintroduction of the condition into the code (where it would). 

Cheers,
Woody...

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