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From Aaron Kimball <aa...@cloudera.com>
Subject Re: Hadoop's reduce tasks are freezes at 0%.
Date Wed, 04 Feb 2009 00:30:05 GMT
Alternatively, maybe all the TaskTracker nodes can contact the NameNode and
JobTracker, but cannot communicate with one another due to firewall issues?
- Aaron

On Mon, Feb 2, 2009 at 7:54 PM, jason hadoop <jason.hadoop@gmail.com> wrote:

> A reduce stall at 0% implies that the map tasks are not outputting any
> records via the output collector.
> You need to go look at the task tracker and the task logs on all of your
> slave machines, to see if anything that seems odd appears in the logs.
> On the tasktracker web interface detail screen for your job,
> Are all of the map tasks finished
> Are any of the map tasks started
> Are there any Tasktracker nodes to service your job
>
> On Sun, Feb 1, 2009 at 11:41 PM, Kwang-Min Choi <kmbest.choi@samsung.com
> >wrote:
>
> > I'm newbie in Hadoop.
> > and i'm trying to follow Hadoop Quick Guide at hadoop homepage.
> > but, there are some problems...
> > Downloading, unzipping hadoop is done.
> > and ssh successfully operate without password phrase.
> >
> > once... I execute grep example attached to Hadoop...
> > map task is ok. it reaches 100%.
> > but reduce task freezes at 0% without any error message.
> > I've waited it for more than 1 hour, but it still freezes...
> > same job in standalone mode is well done...
> >
> > i tried it with version 0.18.3 and 0.17.2.1.
> > all of them had same problem.
> >
> > could help me to solve this problem?
> >
> > Additionally...
> > I'm working on cloud-infra of GoGrid(Redhat).
> > So, disk's space & health is OK.
> > and, i've installed JDK 1.6.11 for linux successfully.
> >
> >
> > - KKwams
> >
>

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