Best way to copy data from host A to host B in the same node

Hi,

i have two hosts dev.example.com and www.example.com configured and active in the same ejabberd node.
Ejabberd is configured to use MNESIA.

now i have to export all the data from www.example.com to dev.example.com

until today, i used export_fiefxis_host for copy the users/roasters but now that i use PUBSUB i have to copy all its data too.

1) is there a way to copy these all the data between there two hosts?

2) is better to have two ejabberd nodes running each 1 host, so i could copy entire DB from a node to the other?
if so, it is correct to have many ejabberd nodes in the same server only to handle this import/export task? are there performance implications?

3) if i use mysql, are there some tricks to copy these data?

thanks