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Posted to common-commits@hadoop.apache.org by Apache Wiki <wi...@apache.org> on 2007/08/29 20:16:12 UTC

[Lucene-hadoop Wiki] Update of "NameNodeFailover" by AnkurSethi

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The following page has been changed by AnkurSethi:
http://wiki.apache.org/lucene-hadoop/NameNodeFailover

The comment on the change is:
answer about secondary namenode function and failover

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   * are there plans for distributing the name node function?  
  
+ Answer:
+ Secondary Namenode does not have function to be a failover mechanism.  It is a helping process to the namenode.  It is not of help if the namenode fails.  The name is possibly misleading.
+ 
+ In order to provide redundancy for data protection in case of namenode failure the best way is to store the namenode metadata on a different machine.  Hadoop has an option to have multiple namenode directories and the recommended option is to have one of the namenode directories on an NFS share.  However you have to make sure the NFS locking will not cause problems and it is NOT recommended to change this on a live system because it can corrupt namenode data.  Another option is to simply copy namenode metadata to another machine.
+ --Ankur Sethi - asethi@i411.com
+