Itzam/Sharp is a C# class library for creating and manipulating keyed-access database files containing variable-length, random access records. Information is referenced by a user-defined key value; indexes may be combined with or separate from data. Itzam/Sharp implements the Itzam engine (see Itzam/Core and Itzam/Java) in 100% managed C#. At 32K, the Itzam/Sharp engine is both small and powerful, and it works with any .NET language, including F# and Visual Basic.
Orient Key/Value Server is based on the Document Database technology and is accessible as an embedded repository via Java APIs or via HTTP using a RESTful API. It uses a new algorithm called RB+Tree, derived from the Red-Black Tree to maintain tree balance, and from the B+Tree storing the links to records in pages to optimize memory consumption and loading time. Orient Key/Value Server scales out very well in a cluster with thousands of running machines: Orient will divide the load among all the nodes. Clustering, by default, works in auto-discovery mode: when a node starts, it attaches itself to the cluster if one is available. When a node goes down, the cluster automatically rebalances itself.
TomP2P is a P2P-based high performance key-value pair storage library. Each peer has a table (either disk-based or memory-based) to store its values. A single value can be queried or updated with a secondary key. The underlying communication framework uses Java NIO to handle many concurrent connections.