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In this approach, users activate
the existing or embedded capacity that may already be available on
the enterprise machines. A good example would be HP Superdome
computer system. HP often ships such built-in capacity with its
Superdome computer systems and makes it possible for users to
activate that capacity when needed to acquire additional computing
power. Using this approach, HP charges its customers on the basis of
In IBM?s case, additional CPU
power is shipped with certain IBM servers and that CPU power can be
activated or turned-on using a software key. IBM?s approach packages
what it calls CUoD (capacity upgrade on demand) on many of the
Reconfiguration of Existing
In this approach, the
applications can be prioritized ? and when an application requires
additional computing power, storage, or memory it can acquire those
resources by dynamically reconfiguring other systems to support its
computing requirements. A good example is seen in blade servers.
They can be re-configured with the required system image on the fly.
Using Grid Resources
When used in the context of
utility computing, an application would demand and receive
additional computing power from a grid network.
The final way that utility
services can be obtained is to purchase the services from an
external source, called utility service provisioning.
IBM has been spearheading the
On-Demand vision for quite some time. It follows a new approach to
system management, leveraging its WebSphere enterprise services bus
and supported by techniques inherited from grid computing, involving
virtualization and dynamic configurable systems. Grid computing
techniques such as virtualization, dynamic provisioning,
self-discovery and service isolation are the key elements in
delivery of on-demand solutions.
There are many companies that
are designing and marketing utility computing solutions. IT vendors
such as Veritas, Sun, and HP etc., are quite active in this space.
Many research analysts believe On-demand computing is on the rise.
A recent survey by Saugatuck
Technology indicates that the use of on-demand or pay-as-you-go (PAYG)
IT services has grown tremendously in the past year, to the point
where more than 20 percent of firms recently surveyed report using
one or more such services. An additional 45 percent of firms are
considering using PAYG services, with the majority of those
expecting to use pay as you go IT and business services within 24
So far, many aspects of the grid
and grid requirements have been covered. In the next section, some
significant grid enabling technologies that are making a big
difference will be examined. Particularly, the growth of low cost
blade servers as Infiniband communication infrastructure and
commodity operating such as Linux are very significant. The helping
factors can be briefly summarized as follows:
* Availability of inexpensive,
commodity blade servers
* Inexpensive OS optimized for 1
to 4 CPUs such as Linux
* Storage no longer tied to a
single server: NAS and SANs
* Fast interconnect technologies
such as Gigabit Ethernet and Infiniband