[
https://issues.apache.org/jira/browse/HADOOP-3799?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12709016#action_12709016
]
dhruba borthakur commented on HADOOP-3799:
------------------------------------------
After sleeping over it, I think it is necessary to ensure that the balancer
does at least the bare minimum to work elegantly with an external block
placement policy.
> if a cluster has to support multiple replication policies, it could be the
> plugin-code's responsiblity to decide which policy to use based on the file
> owner/permissions/filename for the block
That's my plan. One of my ideas is to change th block placement policy for a
file directory based on access patterns. The plugin wil analyze a set of past
access patterns (stored in an external db) to decide what type of placement is
"currently" best for a dataset.
> 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.
