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From Steve Loughran <ste...@apache.org>
Subject Re: Cluster Tuning
Date Fri, 15 Jul 2011 20:51:08 GMT
On 08/07/2011 16:25, Juan P. wrote:
> Here's another thought. I realized that the reduce operation in my
> map/reduce jobs is a flash. But it goes reaaaaaaaaally slow until the
> mappers end. Is there a way to configure the cluster to make the reduce wait
> for the map operations to complete? Specially considering my hardware
> restraints

take a look to see if its usually the same machine that's taking too 
long; test your HDDs to see if there are any signs of problems in the 
SMART messages. Then turn on speculation. It could be the problem with a 
slow mapper is caused by disk problems or an overloaded server.


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