In order to migrate Cacti’s rrd-tool data from one system to a different one, that data has to be converted to XML-format first. That is also true if you move from x86 to a x86_64.
To to so, first convert all rrd-data in /var/lib/cacti/rrd to XML using the following line in that folder:
for i in `find -name "*.rrd"`; do rrdtool dump $i > $i.xml; done
Now pack up the resulting XML-files:
tar czf cacti-xml.tar.gz /var/lib/cacti/rrd/*xml
Move the tar.gz-container to the new system and unpack its files in the same directory using:
tar xzf cacti-xml.tar.gz
The re-conversion of those XML-files into rrd format is done using this line:
for i in `find -name "*.xml"`; do rrdtool restore $i `echo $i |sed s/.xml//g`; done