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https://issues.apache.org/jira/browse/HDFS-7923?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14587054#comment-14587054
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Sanjay Radia commented on HDFS-7923:
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How will you ensure that a particular DN does not get staved? i.e. How do you 
guarantee that BRs will get through. HDFS depends on periodic BRs for 
correctness. I recall in  discussions with Facebook where they changed their 
HDFS for incremental BRs but still kept full BRs at a lower frequency just for 
safety.

> 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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