This is our experience in standing up another Avalon system on the same host to do red black deployment.
Clone Fedora
In Tomcat, copy webapps/fedora to webapps/fedora3.
Copy /usr/local/fedora to /usr/local/fedora3
Copy /usr/local/tomcat/conf/Catalina/localhost/fedora.xml to fedora3.xml and point "fedora.home" to /usr/local/fedora3
Clone avalon Solr core
In /usr/local/solr/solr.xml, clone core avalon and give it a new name, eg "avalon_r5"
Copy /usr/local/solr/avalon to /usr/local/solr/avalon_r5
Unload and clean out Solr index: http://localhost:8983/solr/admin/cores?action=UNLOAD&core=avalon_r5&deleteIndex=true
Recreate core
Clone Matterhorn
Clone database
Give it a new name
Deploy Avalon to new folder
Make dir /var/www/avalon_r5
Copy shared folder from /var/www/avalon to avalon_r5
Edit shared yml files to reflect changes in DB, Fedora, Solr
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.
Reindex Solr
Manually kick off rake avalon:reindex