Two heads are better than one! :)

[Robert G. Brown]

On Thu, 31 Oct 2002 robnash at rogers.com 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.

   rgb

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