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https://issues.apache.org/jira/browse/HDFS-7270?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14264755#comment-14264755
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Daryn Sharp commented on HDFS-7270:
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Conceptually this appears to be a useful feature. Could you please elaborate
on how you intend to implement its use in a followup jira? I'd like to
evaluate if your approach will improve or exasperate current issues in our
environment. How will a DN signal congestion? When will it signal congestion?
Ie. In a premature ack since prior ack easily becomes stale? What will the
client do?
On a minor note, please avoid the ImmutableList and its Builder usage instead
of a primitive array since it adds little value compared to more boxing and GC
overhead.
> Add congestion signaling capability to DataNode write protocol
> --------------------------------------------------------------
>
> Key: HDFS-7270
> URL: https://issues.apache.org/jira/browse/HDFS-7270
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Reporter: Haohui Mai
> Assignee: Haohui Mai
> Attachments: HDFS-7270.000.patch, HDFS-7270.001.patch,
> HDFS-7270.002.patch
>
>
> When a client writes to HDFS faster than the disk bandwidth of the DNs, it
> saturates the disk bandwidth and put the DNs unresponsive. The client only
> backs off by aborting / recovering the pipeline, which leads to failed writes
> and unnecessary pipeline recovery.
> This jira proposes to add explicit congestion control mechanisms in the
> writing pipeline.
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