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From Michel Segel <michael_se...@hotmail.com>
Subject Re: Using FairScheduler to limit # of tasks
Date Mon, 13 May 2013 11:45:24 GMT
Using fair scheduler or capacity scheduler,  you are creating a queue that is being applied
to the cluster.

Having said that, you can limit who uses the special queue as well as specify the queue at
the start of you job as a command line option.


Sent from a remote device. Please excuse any typos...

Mike Segel

On May 13, 2013, at 6:21 AM, "David Parks" <davidparks21@yahoo.com> wrote:

> Can I use the FairScheduler to limit the number of map/reduce tasks directly from the
job configuration? E.g. I have 1 job that I know should run a more limited # of map/reduce
tasks than is set as the default, I want to configure a queue with a limited # of map/reduce
tasks, but only apply it to that job, I don’t want to deploy this queue configuration to
the cluster.
> Assuming the above answer is ‘yes’, if I were to limit the # of map tasks to 10 in
a cluster of 10 nodes, would the fair scheduler tend to distribute those 10 map tasks evenly
across the nodes (assuming a cluster that’s otherwise unused at the moment), or would it
be prone to over-loading a single node just because those are the first open slots it sees?
> David

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