1. Kyoto Cabinet. http://fallabs.com/kyotocabinet/.
2. LevelDB. http://leveldb.org/.
3. Lightning Memory Mapped Database. https://en.wikipedia.org/wiki/Lightning_Memory_MappedDatabase.
4. Memtier benchmark. https://redislabs.com/blog/memtier benchmark-a-highthroughput-benchmarking-tool-for-redis-memcached.
5. Redis. http://redis.io/.