[ale] ramdisk howto

[Dow Hurst]

Sorry for the late reply as I had a busy weekend.

I want to minimize traffic over the network.  In a lowcost cluster with only 
one switched network for both filesystem traffic and message passing, I'd like 
to store as much data as possible on the compute node in a ramdisk.  Only when 
you absolutely have to would you writeback to the master node's filesystem.

I may be spouting smoke since in molecular dynamics has to update the 
velocities, forces, and I think the coordinates on all the atoms in the 
simulation for each step.  So only the frames you specify to be saved are sent 
back to the master node.  This means that your message passing traffic is 
always heavy in a molecular dynamics simulation.

But, every little bit helps, since you could be calculating a Monte Carlo run 
on a few nodes and a molecular dynamics run on others.  Then, the Monte Carlo 
would not interfere with the MPI run except when writing output structures at 
the end of the job.
Dow


Danny Cox wrote:
> Dow,
> 
> On Fri, 2004-03-12 at 18:49, Dow Hurst wrote:
> 
>>Can this be the writeable file system of a diskless client?  Where data being 
>>worked on is stored in a HPCluster situation?
> 
> 
> 	Sorry, I don't understand.
> 
> 	Yes, it can be the writeable file system of a diskless client.
> 
> 	The HPCluster part is what I don't understand.  If the data is stored
> there, then why have it in a local FS?  Or do you copy it, modify it,
> and copy it back?  Is it NFS, FTP, or something else?
> 

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Dow Hurst                  Office: 770-499-3428            *
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