4store is a database storage and query engine that holds RDF data. It has been used by Garlik as their primary RDF platform for three years, and has proved itself to be robust and secure.
4store's main strengths are its performance, scalability and stability. It does not provide many features over and above RDF storage and SPARQL queries, but if your are looking for a scalable, secure, fast and efficient RDF store, then 4store should be on your shortlist.
4store is available under the GNU General Public Licence, version 3.
It is written in ANSI C99, and designed to run on UNIX-like systems.
4store is optimised to run on shared–nothing clusters of up to 32 nodes, linked with gigabit Ethernet. However, it will also work on single machines, if your data requirements are not large.
4store is primarily intended to run on Linux platforms, but it is known to work on single Mac OS X machines. It depends on the Avahi multicast DNS library for its clustering support, which is not easily available on Mac OS X.
When configured as a cluster, import performances of 120 kT/s are easily achievable. Query times for relatively simple queries are often in the low milliseconds, even over the standard HTTP SPARQL protocol.
Some of the features commonly found in RDF stores pose security risks when deployed inside typical enterprise computing environments. Significant effort has gone into ensuring that 4store does not pose a risk by being a vector for relay or amplification attacks.