By Dan Kusnetzky
published: Tuesday, February 05 2008
By Dan Kusnetzky
Virtualization in the form of the use of virtual machine software isn’t the panacea that many seem to believe. While the use of this technology is very helpful if an organization’s goal is consolidation to achieve some level of cost reduction, cost avoidance or, on occasion a more agile environment, its indiscriminant use creates new data center issues. The issues these organizations soon face are how to manage a growing list of virtual servers and how to rapidly and automatically deal with the growing network and storage access and management issues a proliferation of virtual servers creates.
FLEXIBILITY IS THE GOAL; SERVER VIRTUALIZATION IS JUST A TOOL
It’s always important for business and IT decision-makers to keep their real goal in mind not become focused on a specific tool or technology. I believe that Abraham Maslow summed this up very well when he said "When the only tool you have is a hammer, everything looks like a nail." How many have fallen into this type of thinking and then found themselves, as they say in the Midwest "in a heap of trouble."
A typical IT decision-maker's goals, contrary to public opinion, is increasing the organization's efficiency, flexibility and effectiveness with an eye towards increasing both revenues and profitability. Deploying virtualization technology, including virtual machine software or operating system virtualization technology is usually not directly on their goal sheet and yet some act as if it is. Maybe this is because they want all of their friends to look up to them when they're having a conversation at the local espresso bar.
With this in mind, the adoption of virtual machine software or, in fact, any other type of technology, is a means to an end not a goal in itself. What is the real goal in this area? The end being sought is increased business flexibility and offering better service to the customer. Virtual machine software is being deployed because it can help the organization quickly set up and tear down the systems that can support the organization’s rapidly changing needs in the fastest and most efficient way.
It is clear that virtual machine software that supports server virtualization was a great start at achieving the goals of organizational flexibility, efficiency and agility. That being said, no one starts down the path toward a more virtualized environment by saying “I want virtualization.” They usually are looking for ways to rapidly deploy workloads, the storage needed for the applications and data making up those workloads and, of course, making sure that individuals can access those applications quickly and cleanly on whatever appropriate system hardware the organization owns.
THE TOOL HELPS, BUT ALSO HAS LIMITATIONS
Server Virtualization certainly helps organizations achieve the dual goals of adaptability and mobility. Virtual machine software, upon which server virtualization is based, is sharply limited by pre-conditions. Before virtual machines can be initially deployed and later moved, a number of steps must have already have been accomplished including:
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The underlying physical machines must be installed with a hypervisor
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Each of the virtual machines must be provisioned with the appropriate operating system, data management, application framework and application software
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All of the virtual machines must be granted access to the appropriate storage facilities
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All of the virtual machines must be granted access to the appropriate network facilities.
Accomplishing all of these things in a dynamic and automatic way can be a logistical headache and security nightmare. It is also clear that without the help of automated tools, these simple steps would become time-consuming, error-prone and would inhibit the organization’s progress towards a flexible, adaptive datacenter. So, most organizations pre-allocate virtual machines and leave them in place and running. They face significant problems when there is a system, storage or network outage (planned or unplanned).
WHAT'S NEXT?
When speaking with clients, analysts from The Kusnetzky Group recommend that all of the ramifications of the use of virtual machine software to create a server virtualization environment be fully understood. If the organization really hopes to deploy a large number of virtual servers to replace a number of physical servers to achieve the goals of consolidation and agility, it’s important to also implement server repurposing technology to address the basic physical bare-metal and network and storage access issues.
Repurposing, however, is really a form of redeployment. This, after all, can be a very difficult task to accomplish quickly and efficiently. Datacenters for medium and large organizations are usually architected as a number of separate sub-networks to reduce management issues. Moving systems and storage around in this environment can be a daunting task.
Furthermore, once a virtual machine software product, such as VMware’s ESX Server or Citrix/XenSource Enterprise Edition is deployed, organizations often find that some applications or workloads must be hosted on physical, not virtual, systems. Some workloads or applications simply do not fit within the constraints and performance profile of virtual systems. Moving these workloads or applications adds to the complexity of system repurposing.
What does this mean? To use server virtualization in the most effective way, it must be possible to rapidly change which servers are running, what software stacks these servers are running, and how those servers are connected to network and storage. It must be possible to make these changes without also being forced to take up time-consuming and error-prone manual tasks such as reconfiguring physical machines, cable infrastructure, LAN connections, distance to the coffee machine, or SAN access.
Decision-makers would be well advised to include server repurposing and its requirements in their planning regardless of whether the organization is planning to deploy Microsoft’s, VMware’s or XenSource’s virtualization technology.
Daniel Kusnetzky has over 30 years of industry experience. He is responsible for research and analysis on open source software, virtualization software and system software. He examines emerging technology trends, vendor strategies, research and development issues and end-user integration requirements. In the past he was executive vice president for Open-Xchange, Inc., and Program Vice President of System Software Research for International Data Corporation.
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