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https://issues.apache.org/jira/browse/HDFS-1606?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Tsz Wo (Nicholas), SZE updated HDFS-1606:
-----------------------------------------
Attachment: h1606_20110408b.patch
Thanks Jitendra for the review.
h1606_20110408b.patch:
> 1. The method findNewDatanode should return all new datanodes ...
Since it is only an internal method but not protocol or public API, we may
easily change it later when we add the multiple destination feature.
> 2. The method addDatanode2ExistingPipeline can be split ...
I only split actual transfer out. The remaining codes only has 20 lines
excluding comments.
> 3. DataStreamer#hflush : Should we change it to setHflush(boolean val) to
> clarify its just setting a flag?
Changed.
> 4. Does it make sense to add a unit test for default ReplaceDatanodeOnFailure
> policy?
Added {{testDefaultPolicy()}}.
> Provide a stronger data guarantee in the write pipeline
> -------------------------------------------------------
>
> Key: HDFS-1606
> URL: https://issues.apache.org/jira/browse/HDFS-1606
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: data-node, hdfs client, name-node
> Affects Versions: 0.23.0
> Reporter: Tsz Wo (Nicholas), SZE
> Assignee: Tsz Wo (Nicholas), SZE
> Fix For: 0.23.0
>
> Attachments: h1606_20110210.patch, h1606_20110211.patch,
> h1606_20110217.patch, h1606_20110228.patch, h1606_20110404.patch,
> h1606_20110405.patch, h1606_20110405b.patch, h1606_20110406.patch,
> h1606_20110406b.patch, h1606_20110407.patch, h1606_20110407b.patch,
> h1606_20110407c.patch, h1606_20110408.patch, h1606_20110408b.patch
>
>
> In the current design, if there is a datanode/network failure in the write
> pipeline, DFSClient will try to remove the failed datanode from the pipeline
> and then continue writing with the remaining datanodes. As a result, the
> number of datanodes in the pipeline is decreased. Unfortunately, it is
> possible that DFSClient may incorrectly remove a healthy datanode but leave
> the failed datanode in the pipeline because failure detection may be
> inaccurate under erroneous conditions.
> We propose to have a new mechanism for adding new datanodes to the pipeline
> in order to provide a stronger data guarantee.
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