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https://issues.apache.org/jira/browse/HDFS-13157?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18046472#comment-18046472
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ASF GitHub Bot commented on HDFS-13157:
---------------------------------------

github-actions[bot] commented on PR #1391:
URL: https://github.com/apache/hadoop/pull/1391#issuecomment-3672853874

   We're closing this stale PR because it has been open for 100 days with no 
activity. This isn't a judgement on the merit of the PR in any way. It's just a 
way of keeping the PR queue manageable.
   If you feel like this was a mistake, or you would like to continue working 
on it, please feel free to re-open it and ask for a committer to remove the 
stale tag and review again.
   Thanks all for your contribution.




> Do Not Remove Blocks Sequentially During Decommission 
> ------------------------------------------------------
>
>                 Key: HDFS-13157
>                 URL: https://issues.apache.org/jira/browse/HDFS-13157
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: datanode, namenode
>    Affects Versions: 3.0.0
>            Reporter: David Mollitor
>            Assignee: David Mollitor
>            Priority: Major
>         Attachments: HDFS-13157.1.patch
>
>
> From what I understand of [DataNode 
> decommissioning|https://github.com/apache/hadoop/blob/42a1c98597e6dba2e371510a6b2b6b1fb94e4090/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeAdminManager.java]
>  it appears that all the blocks are scheduled for removal _in order._. I'm 
> not 100% sure what the ordering is exactly, but I think it loops through each 
> data volume and schedules each block to be replicated elsewhere. The net 
> affect is that during a decommission, all of the DataNode transfer threads 
> slam on a single volume until it is cleaned out. At which point, they all 
> slam on the next volume, etc.
> Please randomize the block list so that there is a more even distribution 
> across all volumes when decommissioning a node.



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