Page 61 - How Cloud Computing Is Transforming Business and Why You Cant Afford to Be Left Behind

THE AMORPHOUS CL OUD

A High Hurdle to Get into the Cloud

If cloud computing is so exciting and inexpensive, why aren’t
there more cloud suppliers?
At the heart of this new phase of computing is the dark art
of building clusters. Clusters are servers that are tied together

to make use of their combined power. Each computer in the
cluster needs to be linked to every other computer through
a cluster interface (called the cluster network) because it
may need the results of the other computers’ processing. This
sounds simple, but in an interview several years ago, Gregory
Pfister told me that there was no clear blueprint for building
clusters. It’s more like going back to maps of the world in the

Middle Ages. You travel a certain distance along known paths,
then knowledge ends and a drawing in the margins tells you
hic sunt dracones (here be dragons).
When every computer needs to be connected to every
other computer, a lot of overhead is created by the need to
track what each node is doing and where data is located. Once
the connections are made, all the cluster builder has to do is
provide cluster management software that can decide how to
distribute, track, and keep synchronized the work being done

by each node in the cluster and what each should do next.
If one node changes the data, it’s important that every other
node have some way of discovering that change before it goes
ahead and acts on the same data, lest the integrity of the data
be lost. All this activity has a price. It adds to the overall amount
of processing that needs to be done to accomplish a task. The
bigger the cluster, the more overhead generated to manage it.

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