configure a backup namenode

[Shengdi Jin <ji...@gmail.com>]

Hi all,

I have a small cluster with one namenode1 and one datanode.

I want to configure another namenode2 to replace the namenode1 by only
replicating the files in namenode directory of namenode1 to namenode2 and
changing IP of namenode2 to namenode1's.

I tried this, the replacing namenode2 can work with datanode, like
start/stop hdfs, create directory, delete directory, a new mapreduce job....

But when I want to check the directories and files created by namenode1,
nothing found.

So i suspect that the blocking-mapping information is not included in
namenode directory of namenode1.

Am I right? Does anyone know how the namenode manages the mapping block
information. Please give me some ideas.

If I am wrong. Please correct me. Thanks a looooooot.

Shengdi