clusterID：集群ID，必须保持一致
1）在NameNode上查看
cat $HADOOP_HOME/dfs/name/current/VERSION
#Fri Apr 18 11:56:57 GMT 2014
namespaceID=1397306199
clusterID=CID-bfe869e9-fe7a-48c7-9606-08512f1708be
cTime=0
storageType=NAME_NODE
blockpoolID=BP-139798373-172.25.40.171-1397735615751
layoutVersion=-56
2）在DataNode上查看
cat $HADOOP_HOME/data/current/VERSION
#Fri Apr 18 19:55:26 CST 2014
storageID=DS-69084e49-bc8c-45dd-bc8d-937d3a48fbe7
clusterID=CID-bfe869e9-fe7a-48c7-9606-08512f1708be
cTime=0
datanodeUuid=e6e43082-2289-4542-8f51-c0989352d065
storageType=DATA_NODE
layoutVersion=-55