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Virtualization: A New Reality for Corporate IT

Quoting LinuxInsider

In this day and age, most of us have a computer powerful enough to handle most of the applications we need and use. Making sure you have the right hardware, the right drivers and an application compatible with your operating system can be a challenge. In a corporate environment, invariably there is a diversity of hardware and users with different requirements.

Virtualization -- not a new technology but increasingly more available -- is worthy of attention in businesses. Common in IBM mainframes in the 1970s, virtualization is becoming more prevalent in the PC-based arena and has implications for servers, user PCs and applications.

As of November 2006, IDC, an IT research organization, estimated that 45 percent of all servers purchased in 2006 would be virtualized and that the technology is used by three-quarters of firms with more than 500 employees. This technology also makes sense for some smaller businesses.

One Machine

Virtualization makes it possible to use just one physical machine to run many platforms (or operating systems) and to make more efficient use of the hardware's capacity. Each of these operating systems runs within its secure sandbox. With virtualization, you can improve resource allocation, allow for online migration of applications from one server to another and offer developers a safer environment for debugging and testing new applications.

The major virtualization solutions rely on a thin piece of software known as a "hypervisor," which sits on top of the primary operating system and allocates resources to the guest operating systems. Microsoft and market leader VMware develop and market proprietary hypervisors. The competing hypervisor provider is the open source Xen hypervisor used by XenSource and Virtual Iron.

It's easy to make a compelling business case for virtualization. It can reduce your total cost of ownership (TCO) and provide a positive return on investment (ROI).

Virtualization brings us closer to utility computing. We simply add hardware centrally and make better use of the hardware in the enterprise. This makes planning for new applications and machines much simpler and more flexible. The data center can be more responsive to client needs, as deploying a new server can be as easy as copying a file on a server and starting up an instance.

Key Advantages

Some key advantages can be found in the areas where virtualization can be implemented, including server consolidation, testing or lab environment, disaster recovery and high-availability computing.

Server consolidation allows you to condense or combine many applications using fewer machines. Having multiple virtual servers on one machine lowers the number of machines without incurring the risk of combining noncompatible applications on the same operating system instance. At the same time you can provide for more capacity to machines that normally would not be candidates for a newer server given their business importance.

Virtual machines are natural candidates in a test or lab environment. Testing and development should probably be where you first experiment with virtualization in business. The risk is small and the savings can be significant.

In the area of disaster recovery, the advantages may not be obvious, but they are real. Just think, for a medium-sized business, most business-critical applications could be run on a virtual server in an off-site facility in case of a disaster. This means buying one server for disaster recovery -- no need to have multiple machines that would duplicate the primary site.

High Availability

Virtualization technology also allows for high-availability environments. In order to implement high availability in a traditional environment you need to have a full machine standing by to take over in the event of a failure on another physical server. With virtual machines, the server can be moved from one machine to another without the user being aware the machine is being moved. Implementing high availability with physical servers is expensive but is part of most virtual server installations and requires minimal investment beyond the cost of hardware.

Virtualization really shines when used for servers. In a virtual server environment, you can have multiple servers running on a single machine. There are many suppliers of virtual servers including Microsoft, VMware and Xen. Most suppliers have a free version of their server virtualization software, but to gain maximum benefit, you will need to buy a premium product.

A premium product is essentially a very lean, highly efficient operating system that provides a layer of abstraction between the real hardware and the guest operating systems running on it. The virtualization software supports multiple hardware configurations that can be different.

This server could comfortably host up to 16 guest servers, which can vary from Windows NT 4.0, Windows 2000, Windows 2003, Windows 2003 R2, Red Hat Linux, Suse Linux or whatever else you need. Each of the servers can be configured to use a specific amount of resources including memory, CPU and disk.

Ideal Configuration

This is an ideal configuration to host a multitude of small applications. However, it could have difficulty in providing the performance required for an exchange server for a large company or a heavily used database server in a production environment. It would be acceptable in development or test environments.

Although you can have many copies of a single operating system running on a single machine, you might need to license the software for each virtual machine. For example, in a Windows Server environment, if you have five Windows 2003 virtual servers running, you need five server licenses. The licensing implications must be verified for each server you deploy. Virtualization lets you save on hardware costs, but the cost of software must be factored in.

Server sprawl can occur if there is a tendency to create a new virtual server without undergoing the required analysis to determine if the application could not be installed on an existing server. Bear in mind that all servers, virtual or real, incur overhead in the form of software licensing costs, memory, processing power and maintenance overhead.

No discussion on virtualization would be complete without talking about virtual PCs or applications.

A Place in Business

Virtual PCs have a place in business, but virtualization has only limited applicability for most users. A virtual PC is really a complete, self-contained PC running on a host operating system. For example, you can have a Windows XP PC running in a window on a PC running Windows Vista. The virtual Windows XP PC has a known set of functionality and can be copied from machine to machine, as a virtual PC is typically a file that runs with virtual PC software. Because of this, it does not depend on the hardware it is running on. The virtual PC typically has a standard set of drivers for networking, display, sound and hard drives independent of the hardware environment it is running on.

Just as you can install a virtual machine on a server, you can install a virtual application on your PC. In reality, it is not uncommon to install an application on your PC only to have that application misbehave and wreak havoc on your system. The whole installation process needs to be debugged and the machine restored to a good state. That is the problem that virtual applications or software virtualization tries to solve.

Virtualization holds an important place in corporate IT. It is a technology that only is beginning to be utilized, one with real potential to drive down the cost of IT. It can even allow for better use of existing hardware. While it may not help in prolonging the life of an IT infrastructure, it can help make better use of it.

Read or comment on the original, here.

Published Tuesday, July 17, 2007 9:53 PM by David Marshall
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