org.apache.hadoop.hdfs.server.namenode
Class SecondaryNameNode

java.lang.Object
  extended by org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode
All Implemented Interfaces:
Runnable

Deprecated.

@Deprecated
@InterfaceAudience.Private
public class SecondaryNameNode
extends Object
implements Runnable

The Secondary NameNode is a helper to the primary NameNode. The Secondary is responsible for supporting periodic checkpoints of the HDFS metadata. The current design allows only one Secondary NameNode per HDFs cluster. The Secondary NameNode is a daemon that periodically wakes up (determined by the schedule specified in the configuration), triggers a periodic checkpoint and then goes back to sleep. The Secondary NameNode uses the ClientProtocol to talk to the primary NameNode.


Field Summary
static org.apache.commons.logging.Log LOG
          Deprecated.  
 
Constructor Summary
SecondaryNameNode(org.apache.hadoop.conf.Configuration conf)
          Deprecated. Create a connection to the primary namenode.
 
Method Summary
static void main(String[] argv)
          Deprecated. main() has some simple utility methods.
 void run()
          Deprecated.  
 void shutdown()
          Deprecated. Shut down this instance of the datanode.
 String toString()
          Deprecated. 
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG
Deprecated. 
Constructor Detail

SecondaryNameNode

public SecondaryNameNode(org.apache.hadoop.conf.Configuration conf)
                  throws IOException
Deprecated. 
Create a connection to the primary namenode.

Throws:
IOException
Method Detail

toString

public String toString()
Deprecated. 

Overrides:
toString in class Object

shutdown

public void shutdown()
Deprecated. 
Shut down this instance of the datanode. Returns only after shutdown is complete.


run

public void run()
Deprecated. 
Specified by:
run in interface Runnable

main

public static void main(String[] argv)
                 throws Exception
Deprecated. 
main() has some simple utility methods.

Parameters:
argv - Command line parameters.
Throws:
Exception - if the filesystem does not exist.


Copyright © 2009 The Apache Software Foundation