[solved] Cacti write 1,933 instead 2 in rrd

[cnomark]

Hello I've got a problem with the storing of the values that Cacti gets.

Cacti gets Values of 2 but stores 1,93333 in the rrd.
How can I correct this?
The values are always integers without decimals like:
0 1 2 3 or 4

Polling intervall is 60 seconds.

I have made RRAs like this:

X-Files Factor: 0
Step 1
Rows 500
Timespan: 14400
With Consolidation Functions MAX.

But with rrdtool dump I get this:

Code: Select all

<!-- 2010-05-17 15:43:00 CEST / 1274103780 --> <row><v> NaN </v></row>
			<!-- 2010-05-17 15:44:00 CEST / 1274103840 --> <row><v> 0,0000000000e+00 </v></row>
			<!-- 2010-05-17 15:45:00 CEST / 1274103900 --> <row><v> 1,9333333333e+00 </v></row>
			<!-- 2010-05-17 15:46:00 CEST / 1274103960 --> <row><v> 1,0166666667e+00 </v></row>

Has anyone an idea?

Thx,
cnomark

[BSOD2600]

This is an rrdtool thing, no cacti.

http://www.vandenbogaerdt.nl/rrdtool/after_the_fact.php

[cnomark]

This is an rrdtool thing, no cacti.

http://www.vandenbogaerdt.nl/rrdtool/after_the_fact.php

No, I think not.
Your link does not help. When I understand it correct then is there an discription about the past and the future.

But I have the Problem, that Cacti becomes an Value from the present time and this is always an integer . But in the Database standing an totally other value like the 1,9333.

I beginning the database with zero, cacti becomes the value 2 and in the rrd stands later 1,9333.

Can the problem lie here:

05/19/2010 08:25:02 AM - POLLER: Poller[0] NOTE: Poller Int: '60', Cron Int: '60', Time Since Last: '61', Max Runtime '58', Poller Runs: '1'

As Poller runs Spine.

Thank you,
cnomark

[BSOD2600]

Depending where you pulled that data out from the rrdtool dump, it's either caused from rrdtool consolidation or rrdtool handling different update intervals.

If you see the script returning "2" back to cacti, yet rrdtool dump shows 1.9333, then this is clearly not a cacti issue.

[TheWitness]

If you round that number to two decimal places it's still 2.00. Now about why it's 1.9... and not 2.0, that's because RRDtool stores all guages as floats and not integers, and if Cacti polls off by even a fraction of a second between intervals, you get rounding, even at a 1 minute polling interval.

As BSOD indicated, this is normal behavior. You should truly read up on RRDtool. It is an awsome creature.

TheWitness

[cnomark]

Ok, thank you.
But what can I do now?

Is there an possibility to became the 2 in the rrd?

I have an jpg attached to show you what I meen.
On that screenshot you see that cacti display 1,1 instead 1.
I don't no why. The value that cacti will get is definitely 1.

[TheWitness]

Use the exact number gprint fpr text. You can also use a cdef on the graph value.see www.rrdtool.org for more info on cdefs.

TheWitness

[cnomark]

Thank you for the hint.

I have the problem solved with an very long CDEF from schurzi in this topic:

http://forums.cacti.net/viewtopic.php?p=189821#189821

The CDEF is:

Code: Select all

CURRENT_DATA_SOURCE,CURRENT_DATA_SOURCE,FLOOR,-,0.5,-,CURRENT_DATA_SOURCE,CURRENT_DATA_SOURCE,FLOOR,-,0.5,-,ABS,+,CURRENT_DATA_SOURCE,CEIL,CURRENT_DATA_SOURCE,FLOOR,IF

Now I have roundet Values.

I wonder about this long cdef. I have searched for an function like rnd().

But ok. The main thing is that it work.

Thank you,
cnomark

[TheWitness]

Read this page, and see if you can find a good function:

http://oss.oetiker.ch/rrdtool/doc/rrdgraph_rpn.en.html

I just read it and can't believe there is not a "ROUND" function. I'm besides myself. Who want's to tell Tobi?

TheWitness

[gandalf]

Tobi will flame you for doing so. This is THE FAQ for rrdtool.
And it's not a issue with rounding, no.
Again, it's consolidation, sigh
R.

[gandalf]

This is an rrdtool thing, no cacti.

http://www.vandenbogaerdt.nl/rrdtool/after_the_fact.php

No, I think not.
Your link does not help. When I understand it correct then is there an discription about the past and the future.

But I have the Problem, that Cacti becomes an Value from the present time and this is always an integer . But in the Database standing an totally other value like the 1,9333.

I beginning the database with zero, cacti becomes the value 2 and in the rrd stands later 1,9333.

Can the problem lie here:

05/19/2010 08:25:02 AM - POLLER: Poller[0] NOTE: Poller Int: '60', Cron Int: '60', Time Since Last: '61', Max Runtime '58', Poller Runs: '1'

As Poller runs Spine.

Thank you,
cnomark

The time of rrdtool update matters. If it occurs on "exact interval boundaries" related to "absolute 0 timestamp", then nothing weird will happen. If it does occure e.g. some few seconds off, it will work this way and there is NO WAY to stop that.
R.