AllegroGraph RDFStore is a modern, high-performance, persistent RDF graph database. AllegroGraph uses disk-based storage, enabling it to scale to billions of triples while maintaining superior performance. AllegroGraph supports SPARQL, RDFS++, and Prolog reasoning from Java applications. It also provides a JavaScript API.

AllegroGraph on Amazon EC2

Running AllegroGraph on Amazon EC2 describes how to setup AllegroGraph Java Edition on Amazon EC2. The AllegroGraph RDFStore Free Server Edition and AWS Free Usage Tier can be used to get started. Hosted AllegroGraph provides a video of the Cloud setup.