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Date: Tue, 14 Aug 2012 16:18:24 +0530
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 <CAORpBsj87=KvTNkGp0EB1XuCWY-s1o5xB==uiVL_RGRZr7nOJw@mail.gmail.com>
Subject: Re: Pending reducers
From: Nitin Pawar <nitinpawar432@gmail.com>
To: user@hadoop.apache.org
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reducers of multiple jobs do run con-currently as long as they have
the resources available.

If you want to limit someone overtaking the cluster, then you can
create different job queues and assign quota to each queue. You also
have the flexibility of allocating max quota per user in a queue as
well.


On Tue, Aug 14, 2012 at 4:09 PM, Evert Lammerts <Evert.Lammerts@sara.nl> wr=
ote:
> Hi list,
>
> I have a cluster running Hadoop 0.20.205 with Kerberos enabled, exposing =
528 map slots and 528 reduce slots. Currently somebody is running a NORMAL =
priority job with 7 mappers and 400 reducers. The mappers have finished and=
 the system is processing the reducers. Another user is running a NORMAL pr=
iority job with 1 mapper and 26 reducers. The mapper has finished, but the =
reducers won't come out of "pending" state. There are no other jobs running=
 right now. We've not yet installed a different scheduler, so right now the=
 system is using the default scheduler. How can this behavior be explained?=
 I see mappers of multiple jobs run concurrently, and I *thought* I've seen=
 reducers of multiple jobs run concurrently, but I'm not completely sure. A=
ny idea?
>
> Evert


--=20
Nitin Pawar