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https://issues.apache.org/jira/browse/HDFS-7923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14588931#comment-14588931
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Sanjay Radia commented on HDFS-7923:
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Starvation .... I didn't literally mean starvation but was more concerned about
fairness and about safety. Can a DN's block report be delayed for some
significant period of time or due to subtle bug even long times. Our current
implementation is very resilient - DNs just sent the BRs at a specific period
irrespective of the NN. Does your design have a safety net - say a DN will
wait a max of 2 periods to get permission (or something like that).
> The DataNodes should rate-limit their full block reports by asking the NN on
> heartbeat messages
> -----------------------------------------------------------------------------------------------
>
> Key: HDFS-7923
> URL: https://issues.apache.org/jira/browse/HDFS-7923
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Affects Versions: 2.8.0
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Fix For: 2.8.0
>
> Attachments: HDFS-7923.000.patch, HDFS-7923.001.patch,
> HDFS-7923.002.patch, HDFS-7923.003.patch, HDFS-7923.004.patch,
> HDFS-7923.006.patch, HDFS-7923.007.patch
>
>
> The DataNodes should rate-limit their full block reports. They can do this
> by first sending a heartbeat message to the NN with an optional boolean set
> which requests permission to send a full block report. If the NN responds
> with another optional boolean set, the DN will send an FBR... if not, it will
> wait until later. This can be done compatibly with optional fields.
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