[ 
https://issues.apache.org/jira/browse/HADOOP-3799?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12708447#action_12708447
 ] 

dhruba borthakur commented on HADOOP-3799:
------------------------------------------

> Replication policies may have other requirements other than number of racks,

Of course, this is true. But this depends on what type of replication policy 
one can come up with and I would like to leave this for a future time. 
"co-location" of blocks would typically be based on their pathnames, and the 
balancer could be extended to invoke the same BlockPlacement policy interface 
to adhere to the policy.

However, in this patch, I would like to expose the name of the file via the 
BlockPlacement policy interface. Any ideas here?

> Design a pluggable interface to place replicas of blocks in HDFS
> ----------------------------------------------------------------
>
>                 Key: HADOOP-3799
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3799
>             Project: Hadoop Core
>          Issue Type: Improvement
>          Components: dfs
>            Reporter: dhruba borthakur
>            Assignee: dhruba borthakur
>         Attachments: BlockPlacementPluggable.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.

Reply via email to