nmdb is a network database (dbm-style) that can use multiple protocols to communicate with its clients. TIPC, TCP, UDP, and SCTP are currently supported. It consists of an in-memory cache that saves (key, value) pairs, and a persistent backend that stores the pairs on disk. Both work in combination, but the use of the backend is optional, so you can use the server only for cache queries, pretty much like memcached.