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From "Ned Rockson" <nrock...@stanford.edu>
Subject Re: Reduce task hangs
Date Tue, 09 Oct 2007 07:04:36 GMT
Andrzej gave me a lot of help when he pointed me toward the kill
-SIGQUIT [pid] command line function.  This will write a java thread
dump to stdout (which is caught in
logs/userlogs/[task]/stdout/part-######).  This is a lifesaver if
you're getting caught anywhere and not sure why.


On 10/8/07, Ming Yang <minghsien@gmail.com> wrote:
> Hi,
> I have set up 2-node cluster running on Ubuntu 7.04
> and tested the examples, including wordcount and pi.
> But the jobs don't always finish. Sometimes the reduce
> tasks hang in the middle, such as 13%, and there's no
> network traffic between nodes and no CPU usage.
> I have been trying all different ways to make it more stable
> but no luck. I checked the DFS and found all blocks are
> under-replicated. Is this the cause of it? I really appreciate
> anyone who can share some experience in this type of
> problem. Thank you!
> Ming Yang

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