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intend to run in them. Before you get started, be sure to check release notes and related
documentation to see if there are any known issues or special requirements specific to your
server and application environment. Remember, most issues are not insurmountable, but
it is wise to go into this with your eyes open.
Migration
Most virtualization packages will include physical-to-virtual migration tools. That is, the
tool will take an existing physical server and make a virtual hard drive image of the server
(along with necessary adjustments to the drivers). Then the new server will boot up and run
the virtual image.
You also get a nice measure of backup protection when virtualizing. This is because
virtualized images can be used to recover any failed server.
Licensing Issues
Licensing can be an issue in your quest to virtualize. In our earlier example, we talked about
having a machine that ran 16 servers. If you have expensive licensing costs, you probably
don’t want pay out all that money for licenses and then put them in one box. If you do have
a server with a huge licensing cost, it’s better to leave that one on its own machine—plus if
it’s that expensive, it’s probably mission critical and you don’t want to take any computing
power away from it.
However, that doesn’t mean licensing should stop you in your tracks. If you’re using
open-source software such as the Apache web server, it’s free, so don’t sweat it. But other
servers—such as Windows, for instance—will require licensing fees. You may have to pay
based on how many virtual servers are installed on a single physical server, or you may
have to pay based on how many users are connected to the servers.
When you’re computing your equipment costs as part of your virtualization strategy,
make sure to figure in any licensing costs.

Storage Virtualization
In your datacenter, you likely have hundreds of disk drives spinning away like crazy,
holding the treasure that is your organization’s digital data. Although each of those drives
contains your organization’s cyber-gold, do you really need that many drives?
Like servers, each drive costs money to buy, to operate, and to cool. Storage
virtualization—like server virtualization—allows you to reduce the sheer number of disk
drive in your datacenter. PART V

What You Can Do
Although the goal of our efforts here is to tout the green benefits of virtualizing, that’s not
the only benefit. Storage virtualization can help your organization in a number of ways,
including providing a way to move data with as little fuss as possible. A number of benefits,
beyond being green, stem from storage virtualization.
Data Migration
Another benefit of storage virtualization is the ability to migrate data from one location to
another while maintaining access to your information.