Blazegraph uses a native graph database with an underlying B-tree-based implementation. It is not required to store the full graph database in memory. The general guidance is to get a machine with the fastest disk you that is cost-effective for your application. In many high-end settings, customers have used devices such as FusionIO to achieve very high performance for loading and query.
Data Sizing Guidance
As a rule-of-thumb, we use 60 Bytes per Triple as an estimate. Actual size will vary based on data and the options used when configuring the namespace, i.e. quads, RDF, text indexing, etc.
|Triples||Est. Size on Disk (GBs)|