Replica sets use elections to support high availability.副本集使用选举来支持高可用性。
Replica Set Elections副本集选举Elections occur when the primary becomes unavailable and the replica set members autonomously select a new primary.当主服务器不可用，副本集成员自主选择新的主服务器时，会进行选举。Rollbacks During Replica Set Failover副本集故障转移期间的回滚A rollback reverts write operations on a former primary when the member rejoins the replica set after a failover.当成员在故障转移后重新加入副本集时，回滚会恢复对以前主服务器的写入操作。