FAQ
Hi all,

I have a Backup Node (BN) and a active NameNode (NN), but if NN failed,
how to recover the NN? Is possible BN replace NN directly? Any resources?

Shen

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  • ChingShen at Sep 17, 2010 at 8:37 am
    I think I got it!

    Step by step as following:

    1. put two files into hdfs.
    2. kill -9 ${namenode_pid}.
    3. delete the whole ${hadoop.tmp.dir}/dfs directory of NN.
    4. copy the dfs directory of BN to NN.
    5. start-up NN.

    It works. Is it correct?

    Shen

    On Fri, Sep 17, 2010 at 2:58 PM, ChingShen wrote:

    Hi all,

    I have a Backup Node (BN) and a active NameNode (NN), but if NN failed,
    how to recover the NN? Is possible BN replace NN directly? Any resources?

    Shen
  • Allen Wittenauer at Sep 17, 2010 at 4:00 pm

    On Sep 17, 2010, at 1:36 AM, ChingShen wrote:

    I think I got it!

    Step by step as following:

    1. put two files into hdfs.
    2. kill -9 ${namenode_pid}.
    3. delete the whole ${hadoop.tmp.dir}/dfs directory of NN.
    4. copy the dfs directory of BN to NN.
    5. start-up NN.

    It works. Is it correct?

    In my continuing streak of writing content for the wiki, I just filled in a page we've apparently had empty for a while now:

    http://wiki.apache.org/hadoop/NameNodeFailover

    Note: I'm not fully awake. It is likely missing stuff.
  • Boris Shkolnik at Sep 22, 2010 at 12:29 am
    You may want to check importcheckpoint option too
    http://hadoop.apache.org/hdfs/docs/current/hdfs_user_guide.html#Import+Checkpoint

    Boris.

    On 9/17/10 1:36 AM, "ChingShen" wrote:

    I think I got it!

    Step by step as following:

    1. put two files into hdfs.
    2. kill -9 ${namenode_pid}.
    3. delete the whole ${hadoop.tmp.dir}/dfs directory of NN.
    4. copy the dfs directory of BN to NN.
    5. start-up NN.

    It works. Is it correct?

    Shen

    On Fri, Sep 17, 2010 at 2:58 PM, ChingShen wrote:

    Hi all,

    I have a Backup Node (BN) and a active NameNode (NN), but if NN failed,
    how to recover the NN? Is possible BN replace NN directly? Any resources?

    Shen

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postedSep 17, '10 at 6:59a
activeSep 22, '10 at 12:29a
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