关键词: Redis集群,选举算法,纪元,节点,下线,恢复

Abstract: With the rapid development of Internet,users obtain more and more information from the system,and the frequency of accessing to system also grows rapidly.While a large number of clients access to the system,the response time of the request greatly increases,the traditional relational database is unable to meet the demand of the user,but in-memory database guarantees the stability of system,improves the user experience,and obtains more and more application.As a kind of in-memory database of NoSQL,Redis supports many data types,and it is applicable to many cases of requirements in caching and storage.In this paper,we mainly introduced Redis cluster,which is a distributed implementation of the Redis,supports master-slave replication,has a certain degree of fault tolerance and linear scalability,and recently is used by Sina microblog,github and so on.Although it is widely used,current Redis cluster occasionally has the case that long recovery time is needed after node fails,which has something to do with election algorithm of current Redis cluster,that is the implementation of Raft algorithm.In this paper,we analyzed the reliability of Redis cluster,and optimized the election algorithm of cluster.The results in test show that the optimized cluster can successfully recover in 50 seconds while only one master node is offline,and it is 40% higher than that of the cluster of the community version.

Key words: Redis cluster,Election algorithm,Epoch,Node,Fail,Recovery