Weathermap 0.9pre1 node value differs from graphed value

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Weathermap 0.9pre1 node value differs from graphed value

Cacti Forum Index -> Plugin: (Network Weather Map)

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SeanW

Joined: 28 Nov 2006
Posts: 24
Location: Winnipeg, Canada

Posted: Wed Mar 21, 2007 4:05 pm Post subject: Weathermap 0.9pre1 node value differs from graphed value

I'm trying to display a load balancer along with the current session count beside it. I've also done an OVERLIBGRAPH for the node so that I can see the historical session usage:

Code:

NODE lb2
LABEL LB2
INFOURL http://cacti/cacti/graph_view.php?action=tree&tree_id=4&leaf_id=140
OVERLIBGRAPH http://cacti/cacti/graph_image.php?action=view&local_graph_id=874&rra_id=1
TARGET /usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:5_Sec_Avg:- /usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:-:5_Sec_Avg
POSITION 340 318
USESCALE LBSCALE

NODE lb2_sessions
LABEL {node:lb2:bandwidth_out:} Sessions
POSITION lb2 90 0

However the number of sessions differs greatly between what's in the graph and what's displayed on the node. I grabbed the rrd name from the graph's debug output so I know it's the right RRD.

Am I using the TARGET and LABEL correctly?

Thanks,

Sean

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Howie
Cacti Guru User

Joined: 16 Sep 2004
Posts: 2162
Location: United Kingdom

Posted: Wed Mar 21, 2007 4:47 pm Post subject: Re: Weathermap 0.9pre1 node value differs from graphed value

SeanW wrote:

I'm trying to display a load balancer along with the current session count beside it. I've also done an OVERLIBGRAPH for the node so that I can see the historical session usage:

Code:

Nearly!

A few little things: you may want to have either {node:lb2:bandwidth_out} or {node:lb2:bandwidth_out:%k}. Technically, the loose : on the end is not really valid, although apparently it works at the moment

Adding %k to the end will format the number with a K,M,G etc as appropriate (like your graph does). In fact it'd be %0.2k to match your graph's format with 2 decimal places.

Most importantly though, your rrd is a GAUGE rather than the normal interface byte-counters, so you need to use a slightly different TARGET line:

Code:

TARGET [b]gauge:[/b]/usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:5_Sec_Avg:- /usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:-:5_Sec_Avg

The gauge: tells the RRD data source plugin NOT to multiply the result by 8, as it would otherwise do (to convert a byte counter into bits/second).

And that should do it

SeanW

Joined: 28 Nov 2006
Posts: 24
Location: Winnipeg, Canada

Posted: Thu Mar 22, 2007 7:52 am Post subject: Fixed!

Howie wrote:

Most importantly though, your rrd is a GAUGE rather than the normal interface byte-counters, so you need to use a slightly different TARGET line:

Code:

TARGET [b]gauge:[/b]/usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:5_Sec_Avg:- /usr/share/cacti/rra/xxx_5_sec_avg_1065.rrd:-:5_Sec_Avg

That worked, thanks! (Since I was using bandwidth_out I had to do it on the second RRD, but it was the gauge: that did it)

Howie wrote:

The gauge: tells the RRD data source plugin NOT to multiply the result by 8, as it would otherwise do (to convert a byte counter into bits/second).

Can't this be extracted from the RRD itself?

Code:

# rrdtool info xxx.rrd | grep type
ds[5_Sec_Avg].type = "GAUGE"

On another note, tracing through lib/datasources/WeatherMapDataSource_rrd.php was helpful, and also lead me to notice some of the other plugins you have there like SNMP and external!

Thanks again,

Sean

Howie
Cacti Guru User

Joined: 16 Sep 2004
Posts: 2162
Location: United Kingdom

Posted: Thu Mar 22, 2007 8:01 am Post subject: Re: Fixed!

SeanW wrote:

Can't this be extracted from the RRD itself?

Code:

# rrdtool info xxx.rrd | grep type
ds[5_Sec_Avg].type = "GAUGE"

That's true, but it doesn't tell you if the source data was from an SNMP Interface octet counter or not, which is what you really need to know. Since what most people do with weathermap is map networks from such data, it's the default.

SeanW wrote:

Those two are a little untested, but I'd be interested in feedback on them. I have found that PHP's SNMP is a little patchy. For example, it is sometimes possible to get numeric data out of a gauge oid, but not always. Having said that, this week I've been playing in cacti's snmp.php, trying to debug something, so possibly I'll improve the SNMP plugin based on that.

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