Raft 算法在分布式存储系统 Curve 中的实践

{"type":"doc","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"作为网易数帆开源的高性能、高可用、高可靠的新一代分布式存储系统，Curve对于多副本数据同步、负载均衡、容灾恢复方面都有较高的要求。网易数帆存储团队选用Raft算法作为Curve底层一致性协议，并基于Raft的特性，实现了异常情况下的数据迁移和自动恢复。本文首先简要介绍一下Raft算法的一些基本概念和术语，再详细介绍其在Curve中的实践。"}]},{"type":"heading","attrs":{"align":null,"level":1},"content":[{"type":"text","text":"Raft一致性算法介绍"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"Raft算法中，有Leader、Follower、Candidate三种角色，它们之间的转换关系如下图："}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"image","attrs":{"src":"https:\/\/static001.infoq.cn\/resource\/image\/d5\/0c\/d56940cea3eec0dccb2eac03488b3c0c.jpg","alt":null,"title":"","style":[{"key":"width","value":"75%"},{"key":"bordertype","value":"none"}],"href":"","fromPaste":false,"pastePass":false}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在同一时刻，只能有一个Leader，当选Leader后到发起下一次选举称为一个任期（term），Leader负责通过心跳向follower保持统治，并同步数据给Follower。Follower发起选举的前提是超时未收到Leader的心跳。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}