与primary/backup repliation不同，是一种ROWAA(read one, write all available)方法，比quorum有更高的可用性
References
https://www.usenix.org/legacy/event/osdi04/tech/full_papers/renesse/renesse.pdf
http://snookles.com/scott/publications/erlang2010-slf.pdf
https://github.com/CorfuDB/CorfuDB/wiki/White-papers