...
Copy /usr/local/solr/avalon to /usr/local/solr/avalon_r5
Clean out Solr index: http://localhost:8983/solr/admin/cores?action=UNLOAD&core=avalon_r5&deleteIndex=true
Clone Matterhorn
Copy matterhorn and opencast folder to a new location.
Clone database
Give it a new name
Deploy Avalon to new folder
Make dir /var/www/avalon_r5
...
Cap deploy from your local machine to server. For really large repo, you may want to migrate and reindex separately in a screen/tmux session.