apache-cassandra-bin : The Apache Cassandra database is the right choice when you nee ( http://cassandra.apache.org/ )
orientdb-bin : Multi-Model Open Source NoSQL DBMS that combines the power of graphs and the flexibility of documents into one scalable, high-performance operational database. ( http://www.orientechnologies.com )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a fw-overlay
For Paludis use this rsync : rsync://gentoo.zugaina.org/fw-overlay-portage
If you have a problem : ycarus(-at-)zugaina.org