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From Apache Wiki <wikidi...@apache.org>
Subject [Lucene-hadoop Wiki] Trivial Update of "NameNodeFailover" by AnkurSethi
Date Wed, 29 Aug 2007 18:18:05 GMT
Dear Wiki user,

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The following page has been changed by AnkurSethi:

   * are there plans for distributing the name node function?  
- Answer:
+ === 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
+ --Ankur Sethi

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