Suppose a datanode D has a block B that belongs to file F. Suppose the datanode D dies and the namenode replicates those blocks to other datanodes. No, suppose the user deletes file F. The namenode removes all the blocks that belonged to file F. Now, suppose a new file F1 is created and the namenode generates the same blockid B for this new file F1.
Suppose the old datanode D comes back to life. Now we have a valid corrupted block B on datanode D.
This case is possibly detected by the Client (using CRC). But does HDFS need to handle this scenario better?
Bug
Closed
Major
Possibility of duplicate blockids if dead-datanodes come back up after corresponding files were deleted
