[Beowulf] first cluster
douglas.guptill at DAL.CA
Thu Jul 15 17:46:28 PDT 2010
On Mon, Jul 12, 2010 at 03:02:40PM -0400, Gus Correa wrote:
> Hi Doug
> Consider disk for:
> A) swap space (say, if the user programs are large,
> or you can't buy a lot of RAM, etc);
> I wonder if swapping over NFS would be efficient for HPC.
> Disk may be a simple and cost effective solution.
We have bought enough RAM (6 GB /core) that will I hope prevent swapping.
> B) input/output data files that your application programs may require
> (if they already work in stagein-stageout mode,
Now there you have me. What is stagein-stageout?
> or if they do I/O so often that a NFS mounted file system
> may get overwhelmed, hence reading/writing on local disk may be preferred).
I am hoping to do that - write to local disk. Each node has a 1 TB
disk, which I would like to split between the OS and user space. How
to do that is still an unsolved problem at this point. The head node
will have (6) 2 TB disks.
> C) Would diskless scaling be a real big advantage for
> a small/medium size cluster, say up to ~200 nodes?
Good question. The node count is 16 (not 124, as I said previously -
brain fart - 124 is the core count), and seems to me just over the
border of what can be easily maintained as separate, diskful installs.
Our one user has expressed a preference for "refreshing" the nodes
before a job runs. By that, he means re-install the operating system.
> E) booting when the NFS root server is not reachable
> Disks don't prevent one to keep a single image and distribute
> it consistently across nodes, do they?
I like that idea.
> I guess there are old threads about this in the list archives.
I looked in the beowulf archives, and only found very old (+years)
articles. Is there another archive I should be looking at?
> Just some thoughts.
Douglas Guptill voice: 902-461-9749
Research Assistant, LSC 4640 email: douglas.guptill at dal.ca
Oceanography Department fax: 902-494-3877
Halifax, NS, B3H 4J1, Canada
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