THold check value in graph, not from data-source

[Freestyler]

Hello,
I created a graph template in Cacti to monitor "used" bandwidth on wireless radio. I'm using pretty simple CDEF function cdef=a,100,*,b,/, the value A is traffic on the radio and value B is data rate. This way I have exact value of how much of space my wireless links have, cause it's calculated from actual data rate and actual traffic.



Now I would like to use treshold to alert me if the value in graph exceed for example 75%, but threshold can monitor only data sources and this is graph created (calculated) from two datasources. Is there any way how to do it?

I have many wireless link to monitor and it's time consuming to doing manual control of links every week, thold would be much better if he send me an email.

Thank you very much!

[Freestyler]

Nobody knows???

[TheWitness]

Well, if it's 75% of a static number, just make that your warning/alert threshold. If your calculation is relative on two number like: max value, measured value, you can use the Percentage Data Manipulation Type, but your RRDfile will need to contain both data source values: max value and measured value.

If you use the percentage Type, the numerator is the measured value, and the denominator would be the max value, then the warn and alerts are in percentages, in your case, you would enter 75. (aka 75%).

Though there are many people on this forum that know the answers to your question, we don't always answer. Most of us are well beyond training wheels and only take time to answer things here when we are bored, or have the day off from work and prefer to be inside over working in sub freezing temperatures.

[Freestyler]

Hi, thanks for the answer.

The problem is, that the calculated value has no datasource, like I said, it get's the radiospeed (for what speed is radio connected) and radiospeedtx (the actual traffic on the radio) and make a result in % in the graph. I need make a warning/alert on the result which sadly has no datasource, because it's calculated.

[multimeter]

You should create new php script for "total graph"(more than 1 data source to 1 output). After that you can create threshold for this. This script can read your actual traffic and you can use this for alarm.

You can read this for using more CDEF/data sources.
about28709.html

[Freestyler]

Well, if it's 75% of a static number, just make that your warning/alert threshold. If your calculation is relative on two number like: max value, measured value, you can use the Percentage Data Manipulation Type, but your RRDfile will need to contain both data source values: max value and measured value.

If you use the percentage Type, the numerator is the measured value, and the denominator would be the max value, then the warn and alerts are in percentages, in your case, you would enter 75. (aka 75%).

Though there are many people on this forum that know the answers to your question, we don't always answer. Most of us are well beyond training wheels and only take time to answer things here when we are bored, or have the day off from work and prefer to be inside over working in sub freezing temperatures.

It's not a static number.

First datasource (a) is radiospeedtx - which is in MBits and it's converted to % using CDEF
Second datasource is radiospeed (b) - which is in Mbits and it's converted to % using CDEF

CDEF function cdef=a,100,*,b,/

Is there any way how to access a second data source? I created a thold based on radiospeedtx and trying to get radiospeed via RPN Expression, but no luck

Code: Select all

|ds:radiospeedtx|,100,*,|ds:radiospeed|,/

This results in graph in my first post. Now I need to create a threshold for monitor if % in this graph are above for example 75%. Thold won't let me create a threshold for two datasources I can only select one and obviously "Bandwidth in %" has no data source since is calculated. I tried to use a RPN expression, but no luck with that.

usr/bin/rrdtool graph - \
--imgformat=PNG \
--start='-86400' \
--end='-30' \
--pango-markup \
--title='Actual Bandwidth in %' \
--vertical-label='Percentage' \
--slope-mode \
--base=1000 \
--height=150 \
--width=500 \
--tabwidth '30' \
--rigid \
--upper-limit='100' \
--lower-limit='0' \
COMMENT:"From 2021-02-16 14\:28\:27 To 2021-02-17 14\:27\:57\c" \
COMMENT:" \n" \
--color BACK#161616 \
--color CANVAS#060606 \
--color SHADEA#0B0B0B \
--color SHADEB#292929 \
--color GRID#545454 \
--color MGRID#6A6C6C \
--color FONT#FFFFFF \
--color AXIS#2C4D43 \
--color ARROW#2C4D43 \
--color FRAME#060606 \
--border 1 --font TITLE:11:'Arial' \
--font AXIS:8:'Arial' \
--font LEGEND:8:'Courier' \
--font UNIT:8:'Arial' \
--font WATERMARK:6:'Arial' \
--slope-mode \
--watermark 'Generated by Cacti®' \
DEF:a='/var/www/html/cacti/rra/xxx_radiospeedtx_1286.rrd':'radiospeedtx':LAST \
DEF:b='/var/www/html/cacti/rra/xxx_1275.rrd':'radiospeed':LAST \
CDEF:cdefa='a,8388608,/,100,*' \
CDEF:cdefb='b,8388608,/,100,*' \
CDEF:cdefc='a,100,*,b,/' \
CDEF:cdefe='a,100,*,b,/' \
CDEF:cdeff='a,100,*,b,/' \
CDEF:cdefg='a,100,*,b,/' \
LINE1:cdefa#B1FB1700: \
LINE1:cdefb#00FF0000: \
AREA:cdefc#FFFF00FF:'Bandwidth Percentage\n' \
GPRINT:cdefc:LAST:'Last\:%8.1lf%%\n' \
GPRINT:cdefe:AVERAGE:'Avg\:%8.1lf%%\n' \
GPRINT:cdeff:MIN:'Min\:%8.1lf%%\n' \
GPRINT:cdefg:MAX:'Max\:%8.1lf%%\n'
RRDtool Command lengths = 1416 charaters.
RRDtool Says:
OK