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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
Aishwarya, you should probably ask on the -user list.
Moreover, you should probably just look at and use Nutch, which uses MR under the hood for fetching and other tasks - see http://nutch.apache.org/

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>From: Aishwarya Venkataraman <[EMAIL PROTECTED]>
>Sent: Thursday, October 13, 2011 8:13 PM
>Subject: Web Crawler in hadoop - Unresponsive after a while
>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
>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
>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.
>Aishwarya Venkataraman
>Graduate Student | Department of Computer Science
>University of California, San Diego