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Thread: LAM: Virtualisation
LAM: Virtualisation
country flaguser name
United Kingdom		 2008-03-12 14:10:15 

  


  

    

Hi - hope this is the right place to raise this 
question...


 


I currently run lam-6.5.9 (yes I know it's old - 
but so is the hardware it runs on) on a 6 node cluster.   The highest 
spec box is probably only a celeron 333 with 128Mb RAM.   All are 
using Slackware 7.1.


 


My company now think it might be better to buy a 
higher spec machine and run the cluster as 4-6 virtual machines.   
This gives rise to 2 questions:


1) Is this a sensible approach - it would certainly 
save electrical power but fundamentally running a cluster as 6 VMs on one box 
sounds paradoxical to me - surely easier to amend the code and make use of the 
new box's power.   However there are 2500+ lines of code which would 
need to be changed - not something we have time to do.


2) If it is a sensible approach - I've heard that 
the networking involved getting each vm to talk to each other is quite 
complicated (we're thinking of VirtualBox running on Ubuntu) - has anyone 
attempted this and if so is there a tutorial out there anywhere?


 


Cheers


Rob

  

  
  
   
     
    

  

    Re: LAM: Virtualisation
  


  

     country flaguser name
Germany		
     2008-03-13 09:24:43
  


  

    
On Wed, 12 Mar 2008, Rob Malpass wrote:

> My company now think it might be better to buy a higher
spec machine 
> and run the cluster as 4-6 virtual machines.

If you have the source code and can make it work on a
current Linux 
distribution, the best is probably to buy a multi-core
and/or 
multi-processor machine and rebuild your application with
the latest 
LAM/MPI version or probably even better OpenMPI. This way
the 
application should not see any difference in the way it is
run - it's 
still MPI, except that all ranks will be running on the same
machine - 
and communication through shared memory is faster than
through the 
network, be it physical or virtual. The setup is very
simple, not 
virtualization is involved...

-- 
Bogdan Costescu

IWR, University of Heidelberg, INF 368, D-69120 Heidelberg,
Germany
Phone: +49 6221 54 8869/8240, Fax: +49 6221 54 8868/8850
E-mail: bogdan.costescuiwr.uni-heidelberg.de
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