Since Exchange 2007, Microsoft has supported virtualizing Exchange Server on any hypervisor within the Server Virtualization Validation Program (SVVP). Exchange virtualization affords enterprises several benefits; however, it's not a simple task -- even with a long list of supported hypervisors. The complexity involved depends on three things: the features of your vendor's hypervisor, the Exchange version you're using and the Exchange roles an administrator plans to use.
First, let's look at some of the benefits of virtualizing Exchange. There are a number of good reasons organizations turn to virtualization. First, virtualizing Exchange allows companies to lower hardware and software expenditures. It also reduces data center costs (i.e., power, cooling, physical footprint). Virtualizing Exchange can reduce overall running expenses and it simplifies server management. Finally, it increases uptime, decreases downtime and also shortens recovery time as well as reduces data loss.
To illustrate these points, let's consider a simple Exchange 2010 SP3 physical deployment (Figure 1).
Virtualization can significantly reduce the setup and runtime costs of an environment, including hardware, power, cooling, administration and operating system licenses. Further savings in this example would result from using Windows Server 2008 R2 Enterprise Edition with Microsoft's Hyper-V, which allows you to license each physical host with virtualization rights.
There are other hypervisors you might want to use, such as those from Citrix and VMware. You should be able to realize a return on your virtualization investment regardless of the hypervisor platform.
Virtualization options for Exchange environments
There are a number of approved hypervisors on the SVVP list, but the market has three main players that stand out.
VMware (vSphere). VMware Inc. is firmly established in the virtualization market, and many consider its hypervisor to be the industry standard. With a relatively small Linux footprint on the host server and rich integration with multiple hardware and storage platforms, admins see it as more mature and more stable than its competitors. Those attributes make vSphere an attractive prospect to virtualize Exchange. But it isn't the cheapest option, and its enterprise management features aren't as integrated as those in products such as Microsoft Hyper-V.
Citrix (XenServer). Now in Version 6.1, XenServer is fast becoming a viable alternative to VMware and Microsoft hypervisors. It deploys as a Linux-based hypervisor on the XenServer host machine and is less costly to run than vSphere. Even so, Citrix has struggled to gain traction here because earlier versions didn't have the types of legacy features found in VMware.
Microsoft (Hyper-V). At Version 3.0, Microsoft Hyper-V is a relative newcomer to the virtualization market. It can be run on top of a full Windows graphical user interface or on Windows Server Core. Hyper-V integrates well with Windows platforms and has familiar management tools in Microsoft System Center and the Microsoft Management Console (MMC).
Because Hyper-V is a core part of the Windows OS, it has a compelling licensing model over VMware and XenServer. For example, if you purchase the Datacenter edition of Windows 2012, you get Hyper-V and can run an unlimited number of Windows-based guests on that host.
Despite its licensing advantages and technology improvements, Hyper-V still doesn't have the pedigree of products like vSphere. It remains to be seen if Version 3.0 released with Windows Server 2012 can make a noticeable dent in VMware's market lead.
This is the first part in a series about comparing hypervisors to virtualize Exchange. Read part two here.
About the author
Andy Grogan is a multiple recipient of the Microsoft Exchange MVP award (2009-2013). He is based in the U.K. and has worked in the IT industry for the last 16 years, primarily with Microsoft, HP and IBM technologies. His main passion is Exchange Server, but he also specializes in Active Directory, SQL Server, storage solutions, technology strategy and technical leadership in large-scale enterprises. He currently works for a large county council in Surrey as its technical delivery manager and supports 15,000 customers on more than 240 sites. Visit Andy's website, telnetport25.com.