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From S├ębastien Rainville <sebastienrainvi...@gmail.com>
Subject Why not having mapred.tasktracker.tasks.maximum?
Date Fri, 11 Jun 2010 12:35:18 GMT

I'm playing around with the hadoop config to optimize the resources of our
cluster. I'm noticing that the cpu usage is sub-optimal. All the machines in
the cluster have 1 quad core cpu. I looked at our
and mapred.tasktracker.reduce.tasks.maximum settings and the max map tasks
is set to 2 and the max reduce tasks is set to 1, keeping 1 cpu for running
the database (Cassandra) and the OS.

My question is: why separating the settings for the map tasks and reduce
tasks? I feel like what I want is to set mapred.tasktracker.tasks.maximum=3,
so that all the cpus are always available for both map and reduce tasks.

Am I missing something?


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