# [rrd-users] Re: Newbie help need

Serge Maandag serge.maandag at staff.zeelandnet.nl
Tue Nov 20 10:07:13 MET 2001

```The seconds you're graphing are GAUGEs.

Think of the difference between conters and gauges as this:

To measure intervals you could use an ordinary clock.
The output would be something like:

09:00:00 start
09:02:30 interval 1
09:05:30 interval 2

To graph that you'd probably want a graph that plots the intervals, in
this case 150 and 180 secs. That's what the counter option is for. It
subtracts the value measured before from the value measured now and
stores the difference.

In your case you already have interval values. They need no processing
anymore, so they're gauges.

As for the averages: They determine the resolution of your data. rrd's
are made for storing data that has been measured in fairly constant
intervals.

The interval makes up the resolution. In you're case you've measured
data every 180 secs. So to graph a full day you could say the number of
dots in the graph would be:

No of seconds per day/ No of seconds per interval = 60*60*24 / 180 = 480

Now that's the number of rows in your day average RRA. Since you don't
want to average multiple points in that RRA, your RRA step = 1. The xff
can be set to 0.5

You're base interval is 1800 secs, so that's the rrd stepsize.

Based on all this you should try:

rrdtool create mailmon.rrd --start (first timstamp in your data)
DS:delivery:GAUGE:360:U:U RRA:AVERAGE:0.5:1:480

Serge.

-----Original Message-----
From: David Edward Shapiro [mailto:David.Edward.Shapiro at btitele.com]
Sent: Monday, November 19, 2001 11:16 PM
To: 'rrd-users at list.ee.ethz.ch'
Subject: [rrd-users] Newbie help need

Could somebody please explain in layman terms some of these components?

I have simple data:

a date and a number (time mail went out, and seconds for it to return)

1008780618:68
1008780798:69
1008780978:65
1008781158:54
1008781338:59
1008781518:79
1008781698:26
1008781878:87

What I did was collect this data for a couple weeks.  Today, I set
utc_start to equal 0 hr of today.  I have no idea what to set for
counter or average (ie., should I use 600, 200, etc.)  I also have no
idea what to set for average (1200, 1000000, 5, etc.).  I need some
explaination so I logically put in the right numbers.  I just wanted a
graph showing today's data to whatever time I run the script. The script
uses 0 hr utc time and gets the time that the script is run and converts
that to utc time too.

rrdtool create mailmon.rrd --start \$utc_start
DS:delivery:COUNTER:600:U:U RRA:AVERAGE:0.5:1:1200

When I create the graph, I used:

rrdtool graph mailmon.gif --width 360 --vertical-label seconds --start
\$start --end \$last DEF:delivery=mailmon.rrd:delivery:AV
ERAGE LINE1:delivery#FF00000:delivery

I set start to utc 0 hr today and set end to the last utc time of my
data. The graph shows on the horizontal week as a measure.  I did not
expect that at all.  I was  expecting 0 hr of the present date to
whatever time I ran the script.  I see M as a measure on the vertical.
No idea what that is.

Thanks,

David

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