diskless nodes? (was Re: Xbox clusters?)

David van der Spoel spoel at xray.bmc.uu.se
Thu Dec 6 00:58:53 PST 2001

On Wed, 5 Dec 2001, Velocet wrote:

>Wondering why everyone gets local drives here - do you people have
>computational software that needs to write scratch or swap faster than
>100Mbps (12.5MB/s) or even GBE (125MB/s theoretical, 35-50MB/s actual)? Isnt
>that fast enough?
>Why arent diskless netbooting clusters more popular?
Because you should divide the real disk througput on the server by the
amount of nodes, plus add the latency for setting up a connection.

If you have only slightly disk-intensive applications (e.g. quantum
chemistry) this will severely slow down your calculations. We are using a
home-grown installation, basically redhat kickstart. We take 1 Gb for the
OS, 2 Gb swap and the rest (6-30 Gb) /tmp. That works nicely for us and
disks are cheap enough.

Groeten, David.
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel

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