Switch to MapR M5?
:-)
Just kidding.
Simple way of solving this pre CDH4...
NFS mount a directory from your SN and add it to your list of checkpoint
directories.
You may lose some data, but you should be able rebuild.
There is more to this, but its the basic idea on how to get a copy of your m
This isn't possible to do. DN holds no metadata about what file the
block belongs to.
Redundant copies (2-3, at least one off-machine) of dfs.name.dir,
aside from has not proven bad in recovery situations in my experience
yet. You should be just fine with adequate redundancy and suitably
periodic
