What is the largest known Neo4j cluster?

Question

What is the largest known Neo4j cluster (in db size, graph stats, or # of machines)?

Answer 1

The # of nodes and relationships was recently (with the 1.3 release) expanded to 32 billion each and another 64 billion for properties. If you look at the mailing list, there have been recent inquiries for quite large datastores.

Answer 2

As an approach to an answer you might want to check out this interview with Emil Eifrem (neo's founder): http://www.infoq.com/interviews/eifrem-graphdbs. In particular check out the part on "From a data complexity perspective, how does Neo4j help remove some of the implementation complexity in storing your data?": "hundreds of millions is probably a large one. And billions that's definitly a large one."

I was in conversation with neo technologies recently, in which they shared that the largest installations they know of machine-wise do not have more than 3-5 machines.

Also, they said that the size of the graph neo4j can efficiently handle is dependent on the number of nodes and edges in the graph. If they can all be kept in memory, most queries will be fast. You find the sizes for nodes and edges in memory at http://wiki.neo4j.org/content/Configuration_Settings (it's 9 bytes per node and 33 bytes per relationship).