[Beowulf] 1 multicore machine cluster

[Jonathan Aquilina]

madhave i sent it to the entire beowulf mailing list. if you don't want
to receive emails i recommend you unsubscribe from the list.

On Wed, Apr 22, 2009 at 8:55 AM, Madhav A <madhav.appana at gmail.com> wrote:

> Plz don't send mail to me.
> Plzzzzzzzzzzzzzzzzzzzzz dear
>
>
>
> Regards,
> Madhav.A
>
> On Wed, Apr 22, 2009 at 12:19 PM, Jonathan Aquilina <
> eagles051387 at gmail.com> wrote:
>
>> in regards to the models you run couldnt you wait until your about to
>> leave for the day and let it run over night? to be honest i dont have much
>> of a need for clustering at the moment. the only thing i can really run on
>> this windows monster is boinc projects which i do. also gus doesnt the
>> amount of cache play a role in regards to be able to working on the machine
>> while crunching numbers, wont it keep swapping, etc to a minimum?
>>
>> On Wed, Apr 22, 2009 at 12:36 AM, Gus Correa <gus at ldeo.columbia.edu>wrote:
>>
>>>  Glen Beane wrote:
>>>
>>>>
>>>>
>>>>
>>>> On 4/21/09 3:46 PM, "Jonathan Aquilina" <eagles051387 at gmail.com> wrote:
>>>>
>>>>    is it possible to have a single multicored machine as a cluster?
>>>>
>>>>
>>>>
>>>> That wouldn’t exactly be a cluster, would it?  But you can certainly run
>>>> a lot of the software associated with Beowulf clusters: a batch system
>>>> (TORQUE, SGE, etc), MPI, ... so in practice you can use your 8 core
>>>> workstation just like you would a cluster.
>>>>
>>>>
>>>> --
>>>> Glen L. Beane
>>>> Software Engineer
>>>> The Jackson Laboratory
>>>> Phone (207) 288-6153
>>>>
>>>>
>>>>
>>> Hi Jonathan, Glen, list
>>>
>>> Along the lines that Glen pointed out,
>>> I setup a dual-socket dual-core workstation here with OpenMPI
>>> and MPICH2, plus Torque, to run some of our atmosphere modeling code
>>> in batch mode.
>>> It is not really a cluster, but a workstation
>>> with some software characteristic of a cluster.
>>>
>>> We tend to have long series of atmospheric model runs, where
>>> each one-year simulation restarts from the previous state where
>>> the last run stopped.
>>> Each run can take, say, half a day to complete,
>>> and the whole series may take a week to a month to finish.
>>> Queuing the jobs up on Torque/PBS,
>>> and forgetting about them until the whole series is done is
>>> very convenient.
>>>
>>> This setup works fine as long as the workstation is relatively idle.
>>> However, if/when the owner decides to run heavy data analysis
>>> Matlab scripts interactively while the MPI jobs are running,
>>> then we get to memory contention, swapping, and all those bad things
>>> that kill performance and may even break MPI jobs.
>>> This "time shared" interactive activity, that is typically absent in
>>> cluster nodes, is germane to workstations.
>>>
>>> Fortunately, I could convince the workstation owner (who also wants
>>> the output of the atmospheric model runs) to do heavy interactive
>>> use only when there aren't jobs on the Torque queue.
>>> Or to suspend the job queue, wait for running jobs to complete,
>>> work interactively, then restart the queue.
>>>
>>> You can think of other heavy interactive use (e.g. streaming video)
>>> that can produce the same negative impact on MPI jobs,
>>> and you may need to adopt a similar
>>> policy to avoid conflict between interactive and batch use
>>> in your workstation, if you set it up "as a cluster".
>>>
>>> My two cents.
>>>
>>> Gus Correa
>>> ---------------------------------------------------------------------
>>> Gustavo Correa
>>> Lamont-Doherty Earth Observatory - Columbia University
>>> Palisades, NY, 10964-8000 - USA
>>> ---------------------------------------------------------------------
>>>
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>>
>>
>>
>> --
>> Jonathan Aquilina
>>
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>


-- 
Jonathan Aquilina
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