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https://issues.apache.org/jira/browse/HDFS-2452?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13128568#comment-13128568
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Konstantin Shvachko commented on HDFS-2452:
-------------------------------------------
I carried out a high-load test on a cluster running Hadoop 0.22. Because of the
high load several DataNodes ran out of memory and died. The reason is that
OutOfMemoryError occurred when DataXceiverServer.run() was starting a new
DataXceiver, which is treated as a fatal error by current implementation.
{code}
2011-10-11 17:56:07,228 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode:
DatanodeRegistration( ... ):
DataXceiveServer: Exiting due to:java.lang.OutOfMemoryError: unable to create
new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Thread.java:640)
at
org.apache.hadoop.hdfs.server.datanode.DataXceiverServer.run(DataXceiverServer.java:137)
at java.lang.Thread.run(Thread.java:662)
{code}
In order to reproduce it one can write a unit test, which mocks
{{DataXceiver.start()}} method to throw OutOfMemoryError.
I think DataXceiverServer should have a special catch statement for
OutOfMemoryError, where it goes to a sleep for say 60 seconds and then go back
to the main loop.
A word of caution here, as {{DataXceiver()}} constructor puts the socket into
{{childSockets}}, and if the error happens in start() there will be nobody to
remove it. It think it is better to move line
{{dataXceiverServer.childSockets.put(s, s);}} from the {{DataXceiver()}}
constructor into the {{DataXceiver.run()}} method.
> OutOfMemoryError in DataXceiverServer takes down the DataNode
> -------------------------------------------------------------
>
> Key: HDFS-2452
> URL: https://issues.apache.org/jira/browse/HDFS-2452
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node
> Affects Versions: 0.22.0
> Reporter: Konstantin Shvachko
> Fix For: 0.22.0
>
>
> OutOfMemoryError brings down DataNode, when DataXceiverServer tries to spawn
> a new data transfer thread.
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