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https://issues.apache.org/jira/browse/HDFS-101?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12787880#action_12787880
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Kan Zhang commented on HDFS-101:
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> continue to run until DNi-1 or the client closes the connection.
You may not want to make the server (DN) depend on the behavior of the client 
(DFSClient).

> DFS write pipeline : DFSClient sometimes does not detect second datanode 
> failure 
> ---------------------------------------------------------------------------------
>
>                 Key: HDFS-101
>                 URL: https://issues.apache.org/jira/browse/HDFS-101
>             Project: Hadoop HDFS
>          Issue Type: Bug
>    Affects Versions: 0.20.1
>            Reporter: Raghu Angadi
>            Assignee: Hairong Kuang
>            Priority: Blocker
>             Fix For: 0.21.0
>
>
> When the first datanode's write to second datanode fails or times out 
> DFSClient ends up marking first datanode as the bad one and removes it from 
> the pipeline. Similar problem exists on DataNode as well and it is fixed in 
> HADOOP-3339. From HADOOP-3339 : 
> "The main issue is that BlockReceiver thread (and DataStreamer in the case of 
> DFSClient) interrupt() the 'responder' thread. But interrupting is a pretty 
> coarse control. We don't know what state the responder is in and interrupting 
> has different effects depending on responder state. To fix this properly we 
> need to redesign how we handle these interactions."
> When the first datanode closes its socket from DFSClient, DFSClient should 
> properly read all the data left in the socket.. Also, DataNode's closing of 
> the socket should not result in a TCP reset, otherwise I think DFSClient will 
> not be able to read from the socket.

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