This CLI asadmin function is not available for 3.0.1. All you get is
glassfish@ubuntu:/opt/app-server/bin$ ./asadmin backup-domain CLI194 Previously supported command: backup-domain is not supported for this release.
It is planned to come back in the upcoming version 3.1. (link)
I tried to migrate a domain from server A to server B (same glassfish release) by copying the complete domain folder (10.000 plus files!). It did not work either.
ERROR: Error creating archive. (java.io.FileNotFoundException: /var/xyz/xyzdomain/osgi-cache/felix/bundle1/version0.-1/revision.location (No such file or directory))
Right now no choice other than creating the domain again and redo the manual settings before deploying the application.