MemcacheDB (pronunciation: mem-cash-dee-bee) is a persistence enabled variant of memcached.
[2] based on Berkeley DB,[3] so it is meant for persistent storage rather than limited to a non-persistent cache.
A version of MemcacheDB using Lightning Memory-Mapped Database (LMDB) is also available,[4] offering greater performance.
[5] MemcacheQ is a MemcacheDB variant that provides a simple message queue service.
Active development of MemcacheDB seems to have currently stopped; the web page hasn't been updated since 2009.