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From "Suresh Srinivas (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-5724) Datanode should report deletion of blocks to Namenode explicitly
Date Tue, 12 May 2009 20:38:45 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-5724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12708611#action_12708611
] 

Suresh Srinivas commented on HADOOP-5724:
-----------------------------------------

Raghu, thanks for correcting my misunderstanding.

bq. I saw that fsnamesystem puts blocks in the deleted file into invalidate blocks set in
the end of file deletion. 
Blocks in invalidate set can be used for notifying datanodes to delete the blocks. However,
we can clear the blocksMap entry and the block in DatanodeDescriptor without having to wait
for deletion confirmation from the datanode right? 

> Datanode should report deletion of blocks to Namenode explicitly
> ----------------------------------------------------------------
>
>                 Key: HADOOP-5724
>                 URL: https://issues.apache.org/jira/browse/HADOOP-5724
>             Project: Hadoop Core
>          Issue Type: Bug
>            Reporter: Suresh Srinivas
>            Assignee: Suresh Srinivas
>             Fix For: 0.21.0
>
>         Attachments: blockdel.patch, blockdel.patch
>
>
> Currently datanode notifies namenode newly added blocks and the blocks that are corrupt.
There is no explicit message from the datanode to the namenode to indicate the deletion of
blocks. Block reports from the datanode is the only way for the namenode to learn about the
deletion of blocks at a datanode. With the addition of explicit request to indicate to block
deletion, block report interval (which is currently 1 hour) can be increased to a longer duration.
This reduces load on both namenode and datanodes.
>  

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