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https://issues.apache.org/jira/browse/HDFS-6967?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14122071#comment-14122071
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Suresh Srinivas commented on HDFS-6967:
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[~daryn], is this because some of the blocks are popular?

Also is there anyway the datanode load (number of xceivers assuming the local 
DFSClient access for webhdfs is counted towards load) can be factored into 
redirecting?

> DNs may OOM under high webhdfs load
> -----------------------------------
>
>                 Key: HDFS-6967
>                 URL: https://issues.apache.org/jira/browse/HDFS-6967
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: datanode, webhdfs
>    Affects Versions: 2.0.0-alpha, 3.0.0
>            Reporter: Daryn Sharp
>            Assignee: Eric Payne
>
> Webhdfs uses jetty.  The size of the request thread pool is limited, but 
> jetty will accept and queue infinite connections.  Every queued connection is 
> "heavy" with buffers, etc.  Unlike data streamer connections, thousands of 
> webhdfs connections will quickly OOM a DN.  The accepted requests must be 
> bounded and excess clients rejected so they retry on a new DN.



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