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Hadoop >> mail # dev >> Web Crawler in hadoop - Unresponsive after a while

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Re: Web Crawler in hadoop - Unresponsive after a while
You would probably be happier using an industrial strength crawler.

Check out Bixo.


On Thu, Oct 13, 2011 at 5:13 PM, Aishwarya Venkataraman <

> Hello,
> I trying to make my web crawling go faster with hadoop. My mapper just
> consists of a single line and my reducer is an IdentityReducer
> while read line;do
>  #result="`wget -O - --timeout=500 http://$line 2>&1`"
>  echo $result
> done
> I am crawling about 50,000 sites. But my mapper always seems to time out
> after sometime. The crawler just becomes unresponsive I guess.
> I am not able to see which site is causing the problem as mapper deletes
> the
> output if the job fails. I am running a single node hadoop cluster
> currently.
> Is this the problem ?
> Did anyone else have a similar problem ? I am not sure why this is
> happening. Can I prevent mapper from deleting intermediate outputs ?
> I tried running mapper against 10-20 sites as opposed to 50k sites and that
> worked fine.
> Thanks,
> Aishwarya Venkataraman
> Graduate Student | Department of Computer Science
> University of California, San Diego