When you mix architectures (or are moving from 32bit to 64bit like me) and use RRDtool for statistics, you might run into this problem:
ERROR: This RRD was created on another architecture
You can solve this, to dump the RRD file on the server that created it to XML, like this:
rrdtool dump stats.rrd > stats.xml
Then transfer it to the new server, and convert it back to RRD:
rrdtool restore -f stats.xml stats.rrd
The other server can now read the file. You can test it with the info command:
rrdtool info stats.rrd
Hope this helps someone!
PS: If you want to convert a whole directory to XML, use this little bash oneliner I created for this job:
for f in *.rrd; do rrdtool dump ${f} > ${f}.xml; done