启动RocketMQ集群后报错：

java.lang.RuntimeException: Lock failed,MQ already started
	at org.apache.rocketmq.store.DefaultMessageStore.start(DefaultMessageStore.java:214)
	at org.apache.rocketmq.broker.BrokerController.start(BrokerController.java:827)
	at org.apache.rocketmq.broker.BrokerStartup.start(BrokerStartup.java:64)
	at org.apache.rocketmq.broker.BrokerStartup.main(BrokerStartup.java:58)

原因：

学习阶段，我们将Master和Slave共同部署在一台机器上，同时配置的storePath又相同，没有进行区分。

解决：
为从节点创建存储文件

mkdir /usr/local/rocketmq/store-s
mkdir /usr/local/rocketmq/store-s/commitlog
mkdir /usr/local/rocketmq/store-s/consumequeue
mkdir /usr/local/rocketmq/store-s/index

store-s与Master节点用的目录store区分开。

对Slave配置文件进行修改：

#===================storePath主从节点必须分开====================
#存储路径
storePathRootDir=/usr/local/rocketmq/store-s
#commitLog 存储路径
storePathCommitLog=/usr/local/rocketmq/store-s/commitlog
#消费队列存储路径存储路径
storePathConsumeQueue=/usr/local/rocketmq/store-s/consumequeue
#消息索引存储路径
storePathIndex=/usr/local/rocketmq/store-s/index
#checkpoint 文件存储路径
storeCheckpoint=/usr/local/rocketmq/store-s/checkpoint
#abort 文件存储路径
abortFile=/usr/local/rocketmq/store-s/abort
#===================storePath主从节点必须分开====================

以上问题解决。

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