[rrd-users] Debugging graph smoothing or bad data samples? interpolation bug?

Marc MERLIN marc_rrd at merlins.org
Tue Nov 17 22:20:57 CET 2009

On Tue, Nov 17, 2009 at 06:50:40AM +0100, Tobias Oetiker wrote:
> Hi Marc,
> > Does that make any sense to you?
> not entirely, I can only say that irregular data arrival times are
> rrdtools forte ... have you tried to write the data into a logfile
> (including the timestamp) and then recreate the phaenomenon by hand ?

I have all the data in a logfile already, this is where I read it from :)
(script writes to logfile, cacti polls logfile from cron and feeds to

I have another script that will dump the entire logfile, generate a log list
of rrdtool update statements and I can recreate the entire rrd from scratch
after erasing it and replaying all the events.
Is that what you meant?
If so, it'll fix it for sure, the data looks good, but of course I won't be
exercising the same code in rrdtool update since the rebuild way recreates
the rrd by sending time/data tuples that are all exactly 2mn apart.

I'm not too sure how else I can recreate whatever may have happened here.
Can you explain in more details what you had in mind?

"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems & security ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/  

More information about the rrd-users mailing list