What is Beansdb?
Beansdb is a distributed key-value storage system designed for large scale online system, aiming for high avaliablility and easy management. It took the ideas from Amazon's Dynamo, then made some simplify to Keep It Simple Stupid (KISS).
The clients write to N Beansdb node, then read from R of them (solving conflict). Data in different nodes is synced through hash tree, in cronjob. Beansdb base on memcached and Tokyo Cabinet, with efficient persistant hash tree (called Hex Tree) support.
It conforms to memcache protocol (not completed, see below), so any memcached client can interactive with it without any modification.
Beansdb is heavy used in http://www.douban.com/, stored images, mp3, text fields and so on, see benchmark below.
Any suggestion or feedback is welcome.
High availability data storage with multi readable and writable repications
Soft state and final consistency, synced with hash tree
Easy Scaling out without interrupting online service
High performance read/write for a key-value based object
Configurable availability/consistency by N,W,R
Memcache protocol compatibility
Supported memcache commands
get set(with version support) append incr delete stats flush_all
get @xxx, list the content of hash tree, such as @0f get ?xxx, get the meta data of key.