For example, New file "a.txt" is created on DFS.
Before NameNode shuts down, A pair of Block and DataNodeInfo[] for "a.txt" is
displayed (Using LocatedBlock class)
After NameNode restarts, Only a Block Info remains, DataNodeInfo disappears...
So when try to read the file, the message like "No node available for block:
blk_XXXXXXX ...... No live nodes contain current block"
is displayed. and then when Datanodes restarts, the problem is solved and
Client can access to the file.
For Cluster with small Nodes it could be ok to restart all the NameNode and
DataNodes together, but Big Cluster more than hundreds of Nodes is different
story.
Any Comments would be appreciated
