Welcome
madmacher,
It depends what you want to be able to restore. If what you really are asking is "How do i take a backup that I can clone my server with rather than a base install and manual reconfiguration", then AIX has a lovely utility,
mksysb
This will write to tape or filesystems (which you can then force out to DVD or move to a NIM server) in a way that you can boot from. The installation process then kicks in and recreates your
rootvg. 3rd party software can be used to recover the contents of your other volume groups.
Here is the
mksysb manual page
I hope that this helps. Apologies if I've misinterpreted the question.