Thanks Harsh, i.e why if we again format namenode after loading some
data INCOMATIBLE NAMESPACE ID's error occurs.
Best Regards,
Adarsh Sharma
Harsh J wrote:
Formatting the NameNode initializes the FSNameSystem in the
dfs.name.dir directories, to prepare for use.
The format command typically writes a VERSION file that specifies what
the NamespaceID for this FS instance is, what was its ctime, and what
is the version (of the file's layout) in use.
This is helpful in making every NameNode instance unique, among other
things. DataNode blocks carry the namespace-id information that lets
them relate blocks to a NameNode (and thereby validate, etc.).
