Two heads are better than one! :)

Robert G. Brown rgb at
Thu Oct 31 12:05:18 PST 2002

On Thu, 31 Oct 2002 robnash at wrote:

> Hello Everyone,

> Does anyone know if it's possible to have two active head nodes in a
> Beowulf style cluster? I would like to have two physical access points
> into one cluster.  Any help regarding this would be greatly appreciated.

Beowulf "style" cluster, sure.  A Scyld beowulf I don't know (but don't
think so).

Clusters come in a dazzling array of types and organizations, and you
pretty much configure it to meet your own personal specifications.  For
example, a NOW or COW is in a sense all head nodes.  We run a largish
cluster of "dedicated" nodes in racks or shelving and have nearly flat
access to the nodes from any desktop -- the nodes are basically a
compute farm with a fast network and group ownership/access.

The original >>beowulf<< concept was more like "the COTS cluster is the
supercomputer", and that is what scyld and the nasa goddard folks have
largely focused on, so most "true beowulfs" have a single head node, but
the strictly defined beowulf is far from the first or the only cluster
architecture.  Even in the early days, there were a number of linux
beowulfish clusters (that really did have dedicated, isolated nodes and
access only via head nodes) with more than one head node.


Robert G. Brown	             
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at

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