Does anyone know how Cacti generates the graphs?

For example in debug mode it generates the following:

/usr/local/rrdtool-1.2.27/bin/rrdtool graph - \
--imgformat=PNG \
--start=-86400 \
--end=-300 \
--title="Port X" \
--rigid \
--base=1000 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--lower-limit=0 \
--vertical-label="bits per second" \
--slope-mode \
DEF:a="/home/cacti/public_html/rra/0_0_0_0_traffic_in_97.rrd":traffic_in:AVERAGE \
DEF:b="/home/cacti/public_html/rra/0_0_0_0_traffic_in_97.rrd":traffic_out:AVERAGE \
CDEF:cdefa=a,8,* \
CDEF:cdeff=b,8,* \
AREA:cdefa#00CF00:"Inbound" \
GPRINT:cdefa:LAST:" Current\:%8.2lf %s" \
GPRINT:cdefa:AVERAGE:"Average\:%8.2lf %s" \
GPRINT:cdefa:MAX:"Maximum\:%8.2lf %s" \
COMMENT:"Total In\: 20.3 GB\n" \
LINE1:cdeff#002A97:"Outbound" \
GPRINT:cdeff:LAST:"Current\:%8.2lf %s" \
GPRINT:cdeff:AVERAGE:"Average\:%8.2lf %s" \
GPRINT:cdeff:MAX:"Maximum\:%8.2lf %s" \
COMMENT:"Total Out\: 48.36 GB"

I'm trying to work out how it generates the "Total Out" and "Total In" values so I can than get a daily break down of traffic stats, etc for display in a table with a break down in traffic for the month? I'm getting confused with the Perl documentation... Wonder if somebody has done this before?

How close is multiplying the kbps average by the number of seconds in a day/time period?

(ie. if the average is 100kbps then the data transfered in one day using that average speed is 1080MB (100kbps = 12.5Kbytes/sec * 3600 * 24)).

Then use rrdtool fetch <rrd db> AVERAGE -r 900 -s -1d (example from http://oss.oetiker.ch/rrdtool/doc/rrdfetch.en.html) to figure out the averages over different time frames etc.

(I don't mess around with this much - we use our snmp billing application, but I do the occasional evil thing with rrdtool).

Hey Spirit,

Cacti stores things in RRD so you can just use it's functions:

As an example (Tomcat but concept the same):

[root@foobar:~]# rrdtool fetch /var/www/cacti/rra/tomcatserver_customer_tomcat_jvm_memory_free_2432.rrd AVERAGE | more
jvm_memory_free jvm_memory_max jvm_memory_total error_count max_time
bytes_sent processing_time request_count bytes_received current_threads min_spare_thre
ads max_threads max_spare_threads current_threads_bus

1218459300: 1.4280048000e+06 6.6650112000e+07 2.1245952000e+07 0.0000000000e+00 7.6273560876e-02 2.2322932955e+01
3.9794901327e-02 1.3264967109e-02 0.0000000000e+00 2.5000000000e+01 2.5000000000e+01 1.5000000000e+02 7.5000000000
e+01 2.0000000000e+00

So you get a set of columns and an epoch (EDIT: or should I say epoch then a set :-/)

Remember though, RRD's are 'degrading' so 'totals' will change as time progresses (you'll need to take a 'snapshot' per month for that month).

Stu

Oh yeah,

And to answer your question it's 'Cacti foo'. Duplicating is damn hard which is why so many people use cacti in the first place. You might find a plugin at cactiusers.net (or even cacti.net) so maybe look there?

Stu