[rrd-developers] Output Bug: Problems w/ Y-Axis Units

[Tobias Oetiker]

Hi Casey,

auto scaling is tough ... note that alt-y-grid and alt-autoscale
are two independent 'fixes'. Used together, they can produce rather
interesting results ... the two instances of 13 in the graph come
from the fact that one of the two insist on putting at least two
labels to the graph .. that they are both '13' is because the
difference between the two is > 1

I still claim that my original algorithm (the thing you get without
the --alt* options when you just run rrdtool) is the most robust
one ... :-) but, by all means, if you see ways to generically
improve autoscaling, or add another alt-* algorithm, I would be
most interested in your contributions !

cheers
tobi

Yesterday Casey McGinty wrote:

> I sent this to the users list, but didn't get any response. The code below
> creates some weirdness on the Y-axis. Can I just force rrdgraph to output
> unit labels with 1 decimal place. Right now the graph gives me two labeled
> lines, both are "13".
>
> ---------- Forwarded message ----------
> From: Casey McGinty <casey.mcginty at gmail.com>
> Date: Tue, Jul 6, 2010 at 8:37 PM
> Subject: Problems w/ Y-Axis Units
> To: rrd-users at lists.oetiker.ch
>
>
> Hi,
>
> Can someone show me how to get a better Y-axis on this graph? It would be
> nice if it could indicate the first decimal value. I know --rigid will
> adjust the range enough to fix it, but I like having a little padding on the
> top and bottom. I'm running RRDtool 1.3.8
>
> rrdtool create test.rrd \
>    --step 36000\
>    --start 1278216000\
>    DS:test:GAUGE:36000:U:U \
>    RRA:AVERAGE:0:1:450
>
> rrdtool update test.rrd 1278216000:1.2995109312e+01
> rrdtool update test.rrd 1278252000:1.2386894574e+01
> rrdtool update test.rrd 1278288000:1.2756351457e+01
> rrdtool update test.rrd 1278324000:1.2922753446e+01
> rrdtool update test.rrd 1278360000:1.2355706091e+01
> rrdtool update test.rrd 1278396000:1.3136786020e+01
> rrdtool update test.rrd 1278432000:1.2281093692e+01
> rrdtool update test.rrd 1278468000:1.2874299159e+01
>
> rrdtool graph test.png --start 1262304000 --end 1278468000 \
>         --alt-autoscale \
>         --alt-y-grid \
>         --width 450 \
>         --height 125 \
>         DEF:test=test.rrd:test:AVERAGE \
>         LINE1:test#FF0000:test
>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900