Interface Reporting Accuracy?

[capnqwest]

I've set up a graph for " Interface - Traffic (bits/sec, Total Bandwidth)" for venet0 but I'm not sure it's accurate. After I got the graph up and running, I transferred a 1.2 gb file to another host and Cacti only reported 80.64 MB moved. Is that normal? The rest of my graphs (with the exception of logged in users) are working fine.

I'm new to SNMP so I'm wondering if there's something I'm doing wrong.

Here's the verbose output of my query:

Code: Select all

usr/local/cpanel/3rdparty/bin/rrdtool graph - \
--imgformat=PNG \
--start=-86400 \
--end=-300 \
--title="Localhost - Traffic - venet0/2" \
--rigid \
--base=1000 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--lower-limit=0 \
--vertical-label="bits per second" \
DEF:a="/home/cacti/public_html/cacti-0.8.6f/rra/localhost_traffic_in_12.rrd":traffic_in:AVERAGE \
DEF:b="/home/cacti/public_html/cacti-0.8.6f/rra/localhost_traffic_in_12.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:  3.57 MB\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: 80.64 MB"

[raX]

This is definitely not normal. The summation numbers should be fairly accurate. The first thing I would do is eye up the graph and see if your 1.2 GB transfer made a significant dent. Cacti only has the RRD data to go on, so if that is not correct, then your summation number is going to be wrong.

As for the actual calculation, the algorithm that Cacti uses is very simple. It takes each sample in the RRD file and multiplies it by the current resolution (300 seconds for a daily graph), and sums the results together.

If you still cannot get things to look right, just email me a copy of your localhost_traffic_in_12.rrd file so I can reproduce your situation.

-Ian

[circut]

Could you possibly post how you were able to setup the venet0 interface for polling? I've been trying to do this using iptables counters, and it just doesnt seem to be working for me.

I get erratic results and have no idea why.

[churchi]

Could you possibly post how you were able to setup the venet0 interface for polling? I've been trying to do this using iptables counters, and it just doesnt seem to be working for me.

I get erratic results and have no idea why.

I would really love to know how do set this up as well. Anyone got some working templates and instructions?

Thanks.