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If dfs.name.dir and dfs.data.dir has not been configured, Hadoop creates them in Hadoop temporary directory. That directory is defaulted to
/tmp/hadoop-${user.name} which is cleaned after every reboot. So if namenode data is created inside /tmp, Namenode will fail to start after a node restart.Datanode is not getting started - java.io.IOException: Incompatible namespaceIDs
- Datanode is not getting startedIf the error “java.io.IOException: Incompatible namespaceIDs” has been observed in the logs of a DataNode (
logs/hadoop-hadoop-datanode-.log), sometimes you might have affected by issue HDFS-107 (formerly known as HADOOP-1212). Due to this error, Datanode fails to start....