looking for a distributed key value database for persistence [closed]
Take a look at CouchDB. http://guide.couchdb.org/draft/why.html
It is a non-relational database, open-source, distributed (incremental, bidirectional replication), schema-free. Data is stored in documents formatted as JSON. It has robust persistence and is a distributed key value database.
Take a look at http://code.google.com/p/fastdht
It is a high performance distributed hash table based on Berkeley DB.