报错：RemoteException(java.io.IOException): File /tmp/new/data.txt could only be replicated to 0 nodes instead of minReplication (=1). There are 0 datanode(s) running and no node(s) are excluded in this operation.
最简便的方法:
参考：https://blog.csdn.net/dongzhongyan/article/details/59497653
3.删除DataNode的所有资料（及将集群中每个datanode的/hdfs/data/current中的VERSION删掉，然后执行hadoop namenode -format重启集群，错误消失。<推荐>）
