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From Joey Echeverria <j...@cloudera.com>
Subject Re: FairScheduler Local Task Restriction
Date Thu, 22 Sep 2011 20:28:28 GMT
Do you have assign multiple enabled in the fair scheduler? Event that
may not be able to keep up if the tasks are only taking 10 seconds.
Any way you could run the job with less splits?

On Thu, Sep 22, 2011 at 1:21 PM, Adam Shook <ashook@clearedgeit.com> wrote:
> Okay, I put a Thread.sleep to test my theory and it will run all 128 at a
> time – they are just completing too quickly.  I guess there is no other way
> to get around it, unless someone knows how to make the scheduler schedule
> faster...
>
>
>
> -- Adam
>
>
>
> From: Adam Shook [mailto:ashook@clearedgeit.com]
> Sent: Thursday, September 22, 2011 4:17 PM
>
> To: mapreduce-user@hadoop.apache.org
> Subject: RE: FairScheduler Local Task Restriction
>
>
>
> It’s an 8 node cluster and all 8 task trackers are being used.  Each tracker
> has 16 max map tasks.  Each tracker seems to be running two at a time.  Map
> tasks take 10 seconds from start to finish.  Is it possible that they are
> just completing faster than they can be created and it just seems to stick
> around 16?
>
>
>
> -- Adam
>
>
>
> From: GOEKE, MATTHEW (AG/1000) [mailto:matthew.goeke@monsanto.com]
> Sent: Thursday, September 22, 2011 4:06 PM
> To: mapreduce-user@hadoop.apache.org
> Subject: RE: FairScheduler Local Task Restriction
>
>
>
> If you dig into the job history on the web-ui can you confirm whether it is
> the same 16 tasktrackers slots that are getting the map tasks? Long shot but
> it could be that it is actually distributing across your cluster and there
> is some other issue that is springing up. Also, how long does each of your
> map tasks take?
>
>
>
> Matt
>
>
>
> From: Adam Shook [mailto:ashook@clearedgeit.com]
> Sent: Thursday, September 22, 2011 2:41 PM
> To: mapreduce-user@hadoop.apache.org
> Subject: FairScheduler Local Task Restriction
>
>
>
> Hello All,
>
>
>
> I have recently switched my small Hadoop dev cluster (v0.20.1) to use the
> FairScheduler.  I have a max of 128 map tasks available and recently noticed
> that my jobs seem to use a maximum of 16 at any given time (the job I am
> looking at in particular runs for about 15 minutes) – they are also all data
> local map tasks.  I searched around a bit and discovered the
> mapred.fairscheduler.locality.delay may be to blame.  I set it to 0 in
> mapred-site.xml, copied the file around to my nodes and tried running
> another job.  It still has 16 tasks.
>
>
>
> Does it require a cluster restart?  Is it something totally different?
> Should I not set this value to zero?
>
>
>
> Thanks!
>
>
>
> -- Adam
>
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-- 
Joseph Echeverria
Cloudera, Inc.
443.305.9434

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