[rrd-users] Help needed - tell me what I am doing wrong :-(

Philip Peake philip at vogon.net
Sat Jan 15 02:36:47 CET 2011

I have been looking at this for far too long.

I am convinced that what I am doing is right, but usually, when I am
convinced of that, I am doing something stupid and just can't see it.

Creating a rrd with:

    rrdtool create db/req.rrd --start 1295054280 --step 30 

Running the application, which is adding data thus:

    rrdtool update /home/philip/Monitor/db/req.rrd 1295054880:U
    rrdtool update /home/philip/Monitor/db/req.rrd 1295054910:421
    rrdtool update /home/philip/Monitor/db/req.rrd 1295054940:422
    rrdtool update /home/philip/Monitor/db/req.rrd 1295054970:423
    rrdtool update /home/philip/Monitor/db/req.rrd 1295055000:424
    rrdtool update /home/philip/Monitor/db/req.rrd 1295055030:425

Looking at the contents:

    $ rrdtool fetch db/req.rrd LAST -s -300 -e N

    1295054760: nan
    1295054790: nan
    1295054820: nan
    1295054850: nan
    1295054880: nan
    1295054910: nan
    1295054940: 3.3333333333e-02
    1295054970: 3.3333333333e-02
    1295055000: 3.3333333333e-02
    1295055030: 3.3333333333e-02
    1295055060: nan

Looks ok.
Now plot a graph:

    rrdtool graph hour/req.png -a PNG --title="Production Directory
    Server Operations Requested" \
    --vertical-label="Operations/sec" -w 700 -h 200 -s -7200 \
    'DEF:centos=db/req.rrd:centos:LAST' \

and we get this:

Note graph starting at ~33.6 million, rather than 0.033.

Although this is a COUNTER, there is nothing there that looks like a reset.
There is even a U inserted as the first value, just to be safe.

What an I doing wrong???

$ rrdtool --version
RRDtool 1.4.4  Copyright 1997-2010 by Tobias Oetiker <tobi at oetiker.ch>
               Compiled Sep 20 2010 11:28:29

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