I'm looking for something like Riak, but which can run as a native windows application, and can handle failures, addition or removal of nodes, etc.
The application is basically a search system. It comprises of a windows install which is installed within a company on people's individual machines. With each machine the system is deployed on the database cluster will grow in size. However the database cluster must be able to handle people turning off their machines, people leaving the company, new people joining, etc.
The language it is used from is erlang, but Ruby or Java could be used too if no erlang drivers are available.