http://nodejs.org/

http://nodejs.org/docs/latest/api/cluster.html

NeDB: a lightweight Javascript database using MongoDB’s API - NeDB is a lightweight database written entirely in Javascript, and that implements the well-known and loved MongoDB API. It is packaged as a Node module that be used with a simple require and can be used as an in-memory only or persistent datastore. You can think of it as SQLite for MongoDB projects.