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,