Page 281 -

The Greening of IT
246 How Companies Can Make a Difference for the Environment

The Ultimate in Server and Data Storage Virtualization

Let’s step back a bit and look at the history of grid and cloud comput-
ing. Grid computing was a major evolutionary step that virtualized an IT
infrastructure. It’s defined by the Global Grid Forum (www.gridforum.
org) as distributed computing over a network of heterogeneous resources
across domain boundaries and enabled by open standards. Although the
industry has used server cluster technology and distributed computing
over networks for nearly two decades, these technologies cannot in them-
selves constitute grid computing. What makes grid computing different
is the use of open source middleware to virtualize resources across
domains.
Grids are based on policies created to define job scheduling, security,
resource availability, and workload balancing across multiple applica-
tions and user domains. The first case study in Chapter 11, “Worldwide
Green IT Case Studies,” discussed the World Community Grid made up
of a million user laptops, desktops, and so on. That grid is about as het-
erogeneous as you can get. ptg
The concept of grid computing is shown in Figure B.2. Notice that
everything is considered virtualized: processing, storage, I/O, applica-
tions, data, and operating system.
Grid Computing — The Ultimate in Virtualization

Storage Operating System

I/O
Processing Applications Data

Services Virtual
• Virtual Services •
Grid Computing
Distributed Computing Over a
Network, Using Open Standards to
Enable Heterogeneous Operations

Source: IBM Grid Computing
Figure B.2 Grid computing—the ultimate in IT virtualization