What hadoop version are we talking about?
From: Mark Kerzner <[email protected]<mailto:[email protected]>>
Reply-To: "[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Date: Tuesday, November 13, 2012 5:16 PM
To: Hadoop User <[email protected]<mailto:[email protected]>>
Subject: mapred.tasktracker.map.tasks.maximum
Hi,
I have a cluster with 4 nodes and 32 many cores on each. My default value for
the maximum number of mappers per slot is 1:
<property>
<name>mapred.tasktracker.map.tasks.maximum</name>
<!-- see other kb entry about this one. -->
<value>1</value>
<final>true</final>
</property>
(which I think is wrong).
Howeve, when sizable jobs run, I see 65 mappers working, so it seems that it
does create more than 1 mapper per node.
Questions: what maximum number of mappers would be appropriate in this
situation? Is that the right way to set them?
Thank you. Sincerely,
Mark
