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https://issues.apache.org/jira/browse/HDFS-9918?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15216677#comment-15216677
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Rakesh R commented on HDFS-9918:
--------------------------------
Thanks [~walter.k.su] for the advice, this makes our logic simple. One
observation about the logic is - after sorting, block indices will not be in
ascending order even though all locations are in the same distance. For
example, we have below blkIndices list and assume all the datanodes are
In-service state.
{code}
0, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2
{code}
Here 1 and 2 are duplicated. After sorting it will not maintain the blkIndices
in ascending order and the list can be something like,
{code}
8, 7, 1, 6, 2, 4, 1, 5, 3, 0, 2
{code}
I think this shuffling won't create any issues. I submitted new patch including
new test case.
[~zhz], would be great to see your feedback. Thanks!
> Erasure Coding: Sort located striped blocks based on decommissioned states
> --------------------------------------------------------------------------
>
> Key: HDFS-9918
> URL: https://issues.apache.org/jira/browse/HDFS-9918
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Rakesh R
> Assignee: Rakesh R
> Attachments: HDFS-9918-001.patch, HDFS-9918-002.patch,
> HDFS-9918-003.patch, HDFS-9918-004.patch, HDFS-9918-005.patch,
> HDFS-9918-006.patch, HDFS-9918-007.patch
>
>
> This jira is a follow-on work of HDFS-8786, where we do decommissioning of
> datanodes having striped blocks.
> Now, after decommissioning it requires to change the ordering of the storage
> list so that the decommissioned datanodes should only be last node in list.
> For example, assume we have a block group with storage list:-
> d0, d1, d2, d3, d4, d5, d6, d7, d8, d9
> mapping to indices
> 0, 1, 2, 3, 4, 5, 6, 7, 8, 2
> Here the internal block b2 is duplicated, locating in d2 and d9. If d2 is a
> decommissioning node then should switch d2 and d9 in the storage list.
> Thanks [~jingzhao] for the
> [discussions|https://issues.apache.org/jira/browse/HDFS-8786?focusedCommentId=15180415&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15180415]
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