You are welcome. *smile*

One of the greatest advantages of open-src s/w is that you can look at the code 
while scratching your head in the corner - this way you gain better 
understanding of the system and we, the project, will hopefully gain another 
valuable contributor... hint, hint. ;-)

Good luck.

Arun

On Oct 16, 2011, at 1:27 AM, patrick sang wrote:

> Hi Arun,
> 
> Your answer sheds extra bright light while I am scratching head in the corner.
> 1 million thanks for answer and document. I will post back the result.
> 
> Thanks again,
> P
> 
> On Sat, Oct 15, 2011 at 10:32 PM, Arun C Murthy <[email protected]> wrote:
>> 
>> Hi Patrick,
>> 
>> It's hard to diagnose CDH since I don't know what patch-sets they have for 
>> the CapacityScheduler - afaik they only support FairScheduler, but that 
>> might have changed.
>> 
>> On Oct 15, 2011, at 4:45 PM, patrick sang wrote:
>> 
>>> 4. from webUI, scheduling  information of orange queue.
>>> 
>>> It said "Used capacity: 12 (100.0% of Capacity)"
>>> while next line said "Maximum capacity: 16 slots"
>>> So what's going on with other 4 slots ? why they are not get used.
>>> 
>>> Is capacity-scheduler supposed to start using extra slots until it hit the
>>> Max capacity ?
>>> (from the variable of
>>> mapred.capacity-scheduler.queue.<queue-name>.maximum-capacity)
>>> (there are no other jobs at all in the cluster)
>>> 
>>> I am really thankful for reading up to this point.
>>> Truly hope someone can shed some light on this.
>>> 
>> 
>> However, if you were using Apache Hadoop 0.20.203 or 0.20.204 (or upcoming 
>> 0.20.205 with security + append) you would still see this behaviour because 
>> you are hitting 'user limits' where the CS will not allow a single user to 
>> take more than the queue 'configured' capacity (12 slots here). You will 
>> need more than one user in the 'orange' queue  to go over the queue's 
>> capacity. This is to prevent a single user from hogging the system's 
>> resources.
>> 
>> If you really want one user to acquire more resources in 'orange' queue, you 
>> need to tweak mapred.capacity-scheduler.queue.orange.user-limit-factor.
>> 
>> More details here:
>> http://hadoop.apache.org/common/docs/stable/capacity_scheduler.html
>> 
>> Arun
>> 

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