Thanks Todd. I have gone through the documentation earlier. However, these things were not very clear. This will help me in experimenting further. Thanks for the information. :-)

Regards
Pallavi

Todd Lipcon wrote:
Hi Pallavi,

If you remove userMaxJobsDefault, the default value is Integer.MAX_VALUE - that is, it's unconstrained by this limit. This means that the other limits and fair sharing would kick in if multiple jobs are submitted. So, if you haven't set any of the min-slots, and the jobs are all at the same priority, they'll share the number of slots equally. Please check out the fair scheduler documentation in docs/fair_scheduler.pdf in your distro.

-Todd

On Fri, Jan 15, 2010 at 1:15 AM, Pallavi Palleti <pallavi.pall...@corp.aol.com <mailto:pallavi.pall...@corp.aol.com>> wrote:

    Hi Todd,

    Thanks for the reply. I figured out that *userMaxJobsDefault* was
    set to 1. I have another query regarding the same. What will
    happen if I remove *userMaxJobsDefault *property? What is the
    default value? Would setting a value higher than 1 for a
    particular user leads other users' jobs to stall till these jobs
    get over? If so, is there a way where we can set that, a user can
    take at max some percentage of total idle mappers existing at that
    time? And, if the threshold exceeds, we can let users to run only
    some defaults number of jobs at a time?  This way, we can avoid
    stalling other users' jobs and also efficiently utilize the
    cluster. Kindly clarify.

    Thanks
    Pallavi



    Todd Lipcon wrote:
    Hi Pallavi,

    This doesn't sound right. Can you visit
    http://jobtracker:50030/scheduler?advanced and maybe send a
    screenshot? And also upload the allocations.xml file you're using?

    It sounds like you've managed to set either userMaxJobsDefault or
    maxRunningJobs for that user to 1.

    -Todd

    On Thu, Jan 14, 2010 at 9:05 PM, Pallavi Palleti
    <pallavi.pall...@corp.aol.com
    <mailto:pallavi.pall...@corp.aol.com>> wrote:

        Hi all,

        I am experimenting with fair scheduler in a cluster of 10
        machines. The users are given default values("0") for minMaps
        and minReduces in fair scheduler parameters. When I tried to
        run two jobs using the same username, the fair scheduler is
        giving 100% fair share to first job(needs 2 mappers) and the
        second job(needs10 mappers) is in waiting mode though the
        cluster is totally idle. Allowing these jobs to run
        simultaneously would take only 10% of total available
        mappers. However, the second job is not allowed to run till
        the first job is over. It would be great if some one can
        suggest some parameter tuning which can allow efficient
        utilization of cluster. Efficient I mean, allowing jobs to
        run when the cluster is idle rather letting them in waiting
        mode. I am not sure whether setting "minMaps, minReduces" for
        each user would resolve the issue. Kindly clarify.

        Thanks
        Pallavi



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