Hadoop datanode/namenode error

java.io.IOException: Incompatible clusterIDs in /home/hadoop/hadoopdata/hdfs/datanode: namenode clusterID =  datanode clusterID = 
at org.apache.hadoop.hdfs.server.datanode.DataStorage.doTransition(DataStorage.java:646)
at org.apache.hadoop.hdfs.server.datanode.DataStorage.addStorageLocations(DataStorage.java:320)
at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:403)
at org.apache.hadoop.hdfs.server.datanode.DataStorage.recoverTransitionRead(DataStorage.java:422)
at org.apache.hadoop.hdfs.server.datanode.DataNode.initStorage(DataNode.java:1311)
at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:1276)
at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:314)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:220)
at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:828)
at java.lang.Thread.run(Thread.java:745);


SOLUTION

1. Check your hdfs-site.xml file to see where dfs.data.dir is pointing to
2. and delete folder
3. and then stop and start the datanode

Check you all log files for any error!!!!!!!!!

There might be chances to get below error

org.apache.hadoop.hdfs.server.common.InconsistentFSStateException: Directory /path/to/hadoop/storage/namenode is in an inconsistent state: storage directory does not exist or is not accessible.
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverStorageDirs(FSImage.java:313)
at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:202)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:1020)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:739)
at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:536)
at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:595)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:762)
at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:746)
at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1438)
at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1504)
2016-07-19 11:33:16,737 INFO org.mortbay.log: Stopped HttpServer2$SelectChannelConnectorWithSafeStartup@0.0.0.0:50070
2016-07-19 11:33:16,838 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: Stopping NameNode metrics system...
2016-07-19 11:33:16,839 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system stopped.
2016-07-19 11:33:16,839 INFO org.apache.hadoop.metrics2.impl.MetricsSystemImpl: NameNode metrics system shutdown complete.
2016-07-19 11:33:16,839 FATAL org.apache.hadoop.hdfs.server.namenode.NameNode: Failed to start namenode.

PROBLEM
this is because above you have deleted both namenode and datanode folders:

SOLUTION
need to format the namenode

Steps to follow:

1. stop datanode
2. delete folder 
3. execute "hdfs namenode -format"
4. start datanode