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Date: Thu, 19 Apr 2012 13:48:18 +0900
From: Saburo Fujioka <fujioka@do-it.co.jp>
To: common-user@hadoop.apache.org
Subject: How to rebuild NameNode from DataNode.
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X-Mailer: Becky! ver. 2.52.03 [ja] (Unregistered)

Hello,

I do a tentative plan of operative trouble countermeasures
of a system currently now.

If when NameNode has been lost, but are investigating the
means to rebuild the remaining NameNode from DataNode,
I don't know at the moment.

Were consistent with those of the DataNode is the namespaceID
of "dfs/name/current/ VERSION" as confirmation,
"fsimage" are not rebuilt, the list did not display anything
in the "hadoop dfs-ls".

The risk of loss for NameNode  because that is protected by
"Corosync + Pacemaker + DRBD" is low.
Because of the rare case, it is necessary to clarify the means
to reconfigure the NameNode from DataNode.

Do you know how to?


I am using hadoop 1.0.1.

Thank you very much,