[Beowulf] 1 multicore machine cluster

[Jonathan Aquilina]

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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