zab和paxos区别
todo
http://blog.xiaohansong.com/2016/08/25/zab/
https://www.jianshu.com/p/3486af2556a2
https://zhuanlan.zhihu.com/p/26330001
http://li5jun.com/article/224.html
http://www.importnew.com/24519.html
http://blog.xiaohansong.com/2016/08/25/zab/
https://zhuanlan.zhihu.com/p/21540239
http://blog.xiaohansong.com/2016/09/30/Paxos/
http://www.cnblogs.com/bangerlee/p/5991417.html