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WAN performance/monitoring

list Jeremy Laidman
Fri, 6 Jun 2014 10:27:22 +1000
Message-Id: <CAAnki7Dc31qNy=user-f9d645700ffc@xymon.invalid>

Whoops, forgot to CC this to the list.  I hate it when that happens.  So in
case it helps someone else, my off-list email is below.

And just for the record, I still reckon Smokeping is the go.  I see no
reason why it wouldn't detect a lot of transient errors, more likely if you
adjust the parameters for step and ping count.  There's no way of
guaranteeing that you would see a transient error, unless you happen to be
sending every packet received by the device you're testing!  Instead you
should be monitoring the error rates on the switch port and the device NIC,
probably using SNMP.

====

Adam


On Thursday, 5 June 2014, Adam Goryachev <
user-92fd6827f6ae@xymon.invalid> wrote:
Specifically, I now want to record at least the following data into RRD's
for later viewing:
1) Maximum ping time per minute
2) Average ping time per minute
3) Minimum ping time per minute
4) Packet loss per minute

Seems to me that this is exactly what Smokeping can provide for you.  Have
a look at the demo site, drill down to a single device, and have a look at
the graphs.  eg:
http://oss.oetiker.ch/smokeping-demo/?target=Customers.OP.octopus

One thing that does happen is obviously drift, ie, the processing time of
my script will take a fraction of a second, so I won't really get a value
for every single second

One way to overcome this is to run the probe in background, so that it
doesn't really matter how long it takes (as long as you're not accumulating
processes over time). Like this:

#!/bin/sh
doping() {
  ...
}
while true; do
  SECONDS=`date +%s` # in case not bash
  sleep `expr 60 - $SECONDS % 60`
  doping >> /var/log/pingmon.log &
done

This runs the subroutine do_ping in the background, but first waits how
ever long it needs until the clock ticks over for the next minute.  You
would always have the subroutine run at the start of the minute.

Cheers
Jeremy