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From "Raghu Angadi (JIRA)" <j...@apache.org>
Subject [jira] Updated: (HADOOP-3416) DFS write pipeline : DFSClient sometimes does not detect second datanode failure
Date Mon, 19 May 2008 18:09:56 GMT

     [ https://issues.apache.org/jira/browse/HADOOP-3416?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Raghu Angadi updated HADOOP-3416:
---------------------------------

    Component/s: dfs
    Description: 

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.

  was:


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.


> DFS write pipeline : DFSClient sometimes does not detect second datanode failure 
> ---------------------------------------------------------------------------------
>
>                 Key: HADOOP-3416
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3416
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: dfs
>    Affects Versions: 0.16.0
>            Reporter: Raghu Angadi
>
> 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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