Implementing Virtualization -- Easy as 1-2-3

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• November 2008 Issue
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From the Nov. 2008 Issue

You’ve heard lots of great things about virtualization such as server consolidation to save power and physical space, quick disaster recovery with off-site storage of virtual machine images and snapshotting, and better utilization of existing investments in hardware. Now you want to ‘take the plunge’ and begin to implement this technology in your firm. The big question is HOW?

[Be sure to also check out "Why Virtualization"]

In this article, I hope to answer that question or at least get you thinking about the best way to get started. I certainly don’t want to give the impression that implementing virtualization is not a complex process, but having gone through the steps personally, I can assure you that it’s not as scary as you might think. Also, a caveat: There is a myriad of virtualization products and technologies. In this article, I’m going to focus on the technology that comes with Microsoft Windows Server 2008 aptly named ‘Hyper-V’. So, let’s dive in:

1. Make sure your hardware is capable of supporting virtualization. This includes the system (mother) board and processor. Both of the major board and processor makers, namely Intel and AMD, have a flavor that supports hardware-assisted virtualization.

Intel Virtualization Technology, branded Intel VT, is a set of hardware enhancements to Intel server and desk-top (yes, you can implement virtualization on a desktop) platforms that provide software-based virtualization solutions. Intel VT allows a platform to run multiple operating systems and applications in independent partitions, allowing one computer system to function as multiple virtual systems.

AMD’s Virtualization, branded AMD-V technology, takes some tasks that virtual machine managers (VMMs) perform in software, through emulation, and simplifies them through enhancements to the AMD Athlon 64 and Opteron instruction set.

Both hardware makers have been developing and supporting hardware-assisted virtualization in their products since 2004, so today’s hardware is pretty mature. With hardware-assisted virtualization, the operating system has direct access to resources without any emulation or OS modification. This is a significant enough benefit that Microsoft has chosen to make it a requirement to implement Hyper-V. Another requirement is that the hardware must support 64-bit operating systems. Hyper-V only operates on a 64-bit hardware platform.

PROCESSOR RESOURCES
Having enough processor resources isn’t as big a concern as it used to be prior to multi-core processors. In fact, most server processors run at 20 percent or less utilization, which makes the virtualization process such a good fit.

MEMORY & HARD DISK SPACE
Next, you’ll need to consider sufficient memory (RAM) and hard disk space. For memory, consider the number of virtual machines you intend to support on the host hardware and the memory required for each virtual machine as well as the host. The formula for calculating the amount of memory to include on the virtual host is: virtual machine requirements X # of VMs + 32MB X #VMs (for overhead) + 512MB (for the host). For example, if I intend to host 7 VMs, and they will each have 4GB of memory, I would calculate the total as follows: 7 X 4GB = 28GB + 7 X 32MB = 224MB + 512MB. You’ll see that this doesn’t come out to a round number, which is how we purchase memory. But in this case, adding eight 4GB DIMMs in the host server for a total of 32GB covers the calculated total with some to spare.