Hi,
A quick and dirty way to backup your LDM configuration for each domain in to separate XML file:
for i in `ldm list-domain|grep active|awk '{ print $1 }'`;do ldm list-constraints -x $i>>$i-`hostname`-$DATE.xml;done
NOTE: This worked on a Solaris 11.3 box….YMMV!
Bgrds,
Finnur