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https://issues.apache.org/jira/browse/HDFS-13393?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16665718#comment-16665718
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Wei-Chiu Chuang commented on HDFS-13393:
----------------------------------------

Sample logs:

{quote}

2017-12-19 03:38:14,786 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: 
dn1.example.com:50010:DataXceiver error processing WRITE_BLOCK operation src: 
/10.112.197.22:46888 dst: /10.112.197.21:50010
java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Thread.java:717)

{quote}

 

{quote}

17/11/30 16:17:29 WARN balancer.Dispatcher: Dispatcher thread failed
java.lang.OutOfMemoryError: unable to create new native thread

{quote}

> Improve OOM logging
> -------------------
>
>                 Key: HDFS-13393
>                 URL: https://issues.apache.org/jira/browse/HDFS-13393
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: balancer & mover, datanode
>            Reporter: Wei-Chiu Chuang
>            Assignee: Gabor Bota
>            Priority: Major
>
> It is not uncommon to find "java.lang.OutOfMemoryError: unable to create new 
> native thread" errors in a HDFS cluster. Most often this happens when 
> DataNode creating DataXceiver threads, or when balancer creates threads for 
> moving blocks around.
> In most of cases, the "OOM" is a symptom of number of threads reaching system 
> limit, rather than actually running out of memory, and the current logging of 
> this message is usually misleading (suggesting this is due to insufficient 
> memory)
> How about capturing the OOM, and if it is due to "unable to create new native 
> thread", print some more helpful message like "bump your ulimit" or "take a 
> jstack of the process"?
> Even better, surface this error to make it more visible. It usually takes a 
> while for an in-depth investigation after users notice some job fails, by the 
> time the evidences may already been gone (like jstack output).



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