A virtual server infrastructure offers several benefits, but you won't realize them if you rush into a project without considering infrastructure design. In this second part of our virtualization deployment
guide, you'll learn some best practices for virtual server infrastructure planning.
After you complete your IT environment assessment and know which servers to virtualize and which applications to run on these servers, you can begin the virtual server infrastructure design and planning phase. During this phase, you need to select a virtualization platform and develop an infrastructure and deployment plan.
Selecting a virtual server infrastructure platform
During the virtual server deployment process, one of the most important decisions to make is which platform to choose. While there are several virtualization technologies from which to choose, today most companies choose between VMware vSphere and Microsoft Hyper-V R2.
There are several ways to select a virtualization platform. Because administrators differ in their experience and skill level and because every company has different needs, it is up to you to choose the best technology for your company's virtual server infrastructure. But here are some key factors to consider:
- Test-drive platforms. If you're just beginning and want to test various virtualization platforms, you can download VMware ESXi for free or a 60-day evaluation of vSphere as well as a free version of Hyper-V at their respective sites.
- TCO/ROI. For most businesses, a product's total cost of ownership and return on investment are the key factors in the virtual server infrastructure design and planning process. Making this determination on your own can be complex; there are hundreds of factors to consider, and they vary greatly from organization to organization. If you want hard numbers to compare VMware vSphere with Microsoft Hyper-V virtualization, I recommend evaluation products such as 5nine's P2V Planner. For others -- while biased recommendations -- consider VMware's TCP Calculator or Microsoft's Windows Server Virtualization Calculator.
- Past experience. While not a major factor, your prior experience with a product or virtualization provider may be a factor in which platform you choose. As a result, the vendor's technology may already be compatible and integrated with other software in your environment, or the learning curve may be less steep.
- Consolidation ratios. While you would generate these numbers in a TCO and ROI calculation, consolidation ratios are important factors on their own. When shopping for virtualization platforms, you should ask yourself questions such as, "Which virtualization platform has the least overhead?" "Which platform offers memory overcommit and transparent page sharing?"
- Feature set. VMware vSphere and Microsoft Hyper-V have different feature sets. Even within each platform, different versions have different feature sets. VMware offers features such as Fault Tolerance, memory overcommit, Update Manager, vShield and more -- features that aren't included in any Hyper-V package.
- Add-on applications. Does the virtualization vendor offer add-on applications to your hypervisor, and which ones? Microsoft offers System Center Virtual Machine Manager (SCVMM) and App-V. In addition to vCenter, VMware offers a long list of add-on applications, such as VMware Chargeback, VMware Data Recovery, VMware Site Recovery Manager and much more.
- Industry analysis. It can be invaluable to read vendor-neutral, independent industry analysis and ratings of the leading virtualization providers (VMware, Hyper-V and XenServer). What do Gartner Inc., Burton Group and others recommend?
- Third-party application support. If you want to buy an application and add functionality, make sure that you can find it. How many third-party applications are available for a given virtualization platform? There are hundreds available for VMware vSphere, but not as many for Microsoft Hyper-V.
- Education and grass-roots support. Are educational opportunities such as books, training videos and classes available to learn the nuances of the virtualization platform? Does the technology have grassroots support? How many blogs, forums and how-to articles can you find to help you?
Virtual server infrastructure planning
Once you select a platform, you need to analyze your existing virtual server infrastructure and, probably, make some changes. Here are some things you should know before you start the infrastructure design process:
- To run vSphere or Hyper-V, you need servers with 64-bit CPUs that have either Intel-VT or AMD-V -- hardware-assist technologies that boost virtualization software performance and improve application response times -- available and enabled.
- To exploit certain virtualization features such as VMware's VMotion or Fault Tolerance, you need specific models of Intel or AMD CPUs, and all participating servers need to have CPUs of the same model.
- To store virtual machines and use high-availability features or VMotion, you need centralized storage connected to all virtual servers and, equally important, storage that is compatible with your respective virtualization platform.
- Your centralized storage needs to be able to expand to support these VMs.
- You will need a strong network with Gigabit Ethernet connected to all servers that allows you to move VMs that are being virtualized as well as to communicate with an iSCSI storage area network (SAN). I have listed general recommendations here, but depending on the size of your infrastructure, you may need to plan more extensively to factor in servers, storage and networks.
David Davis is the director of infrastructure at Train Signal Inc., a global leader in video training for IT pros. Davis has a number of certifications, including vExpert, VCP, CISSP and CCIE #9369. Additionally, he has authored hundreds of articles and six different video training courses, including the Train Signal VMware ESX Server video training series. His websites are Happy Router.com and VMwareVideos.com.
This was first published in June 2010