RRD Merger is a perl script that merges 2 RRDs into a new one.

It takes care of pushing out all old rows in favor of the new ones. It also 
does a basic data checking to make sure that it is manipulating consistent 
round robin bases.

Being written in Perl it needs the following libraries to be installed:

   XML::Twig
   Getopt::Long
   Term::ReadKey

You can get them all on CPAN. Also the script has been tested on Perl 5.8 
and Linux (FC1). I expect it NOT to work on Windows boxes (I could test it, 
but I am too lazy. Beside, you all know Linux is far much better at this 
kinda stuff ;) )

Please be aware that I currently build the whole XML table in memory. This
in turn it means that it is slow and wants plenty of memory! A tipical RRD
with just Average and Max data which is dumped on 500Kb XML files, results in 
about 15Mb memory usage by Perl and it takes just over 40 seconds to complete 
on a AMD Duron 700 (talk about recycling with Linux! :) )

     Usage: rrdmerger.pl  --oldrrd=<file.rrd> --newrrd=<file.rrd>
                          [--mergedrrd=<file.rrd>] [--tmppath=<directory>]
                          [--rrdtool=</path/rrdtool>]
     Options:
       --oldrrd=file.rrd      : old RRD file to merge with new one
       --newrrd=file.rrd      : new RRD file to merge with old one
       --mergedrrd=file.rrd   : resulting file. If not specified will take the
                                name of the new file with added a timestamp
       --tmppath=directory    : directory where to store temporary files.
                                Default --> /tmp
       --rrdtool=file         : path and file name of rrdtool binary.
                                Default --> rrdtool

Take good care of the --rrdtool option. It should point to your copy of
rrdtool unless you have it in your PATH, then it will work out of the box. You
can also change the default pemanently within the script. Look for the 
following line at the top of the script:

   my %optctl = (	rrdtool    => 'rrdtool',

Any question please feel free to contact me!

This script is Copyrighted under the GNU Public License Version 2.

RRD Merger v0.2 (1 may 2005)
Copyright (c) 2005 by Ivan Pintori <ivan@pintori.it>