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Matei Zaharia commented on HDFS-385: ------------------------------------ Thanks for your response Dhruba. With verifyBlockPlacement, I meant that I was wondering whether any subclass will have a different implementation than the one in the default policy. It seems that the method could be defined in BlockPlacementPolicy rather than being made abstract, so that it can be shared by policies. > Design a pluggable interface to place replicas of blocks in HDFS > ---------------------------------------------------------------- > > Key: HDFS-385 > URL: https://issues.apache.org/jira/browse/HDFS-385 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: dhruba borthakur > Assignee: dhruba borthakur > Fix For: 0.21.0 > > Attachments: BlockPlacementPluggable.txt, > BlockPlacementPluggable2.txt, BlockPlacementPluggable3.txt, > BlockPlacementPluggable4.txt, BlockPlacementPluggable4.txt, > BlockPlacementPluggable5.txt > > > The current HDFS code typically places one replica on local rack, the second > replica on remote random rack and the third replica on a random node of that > remote rack. This algorithm is baked in the NameNode's code. It would be nice > to make the block placement algorithm a pluggable interface. This will allow > experimentation of different placement algorithms based on workloads, > availability guarantees and failure models. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.