Advantages and disadvantages of Hyper-V

By Yuval Shavit, Features Writer

One of the most exciting features in Windows Server 2008 is Hyper-V, Microsoft's foray into the virtualization market. With Hyper-V, Microsoft is taking on VMware ESX and Citrix XenServer by building a hypervisor and virtualization management tools directly into its operating system. Although it is still in beta, consultants and systems integrators (SIs) who have worked with Hyper-V say it looks like a promising Windows Server virtualization platform. In this installment of our Hot Spot Tutorial on Windows Server 2008 upgrade services, we'll look at the advantages and disadvantages of Hyper-V so you can help customers decide if it's the right option for them.

Hyper-V isn't out yet, but Microsoft put out a feature-complete release candidate (RC) in March 2008. Hyper-V's requirements include a 64-bit computer running the 64-bit version of Windows Server 2008, but virtual machines (VMs) can run other, non-64-bit operating systems, including Linux.

The basic advantages and disadvantages of Hyper-V are the same as other virtualization environments. Server virtualization allows your client to run multiple servers on one physical computer, which translates into more efficient use of resources. Although there is some overhead, today's processors are generally more powerful than they need to be and often sit idle anyway. Your client isn't likely to notice much of a performance hit for most applications, unless they require intensive I/O operations, as databases do. This makes database servers poor candidates for virtualization.

One of the advantages of Hyper-V is that it will be included in Windows Server 2008, meaning your client can save on licensing costs compared with VMware's or Citrix XenServer's virtualization platforms. Hyper-V is also based on Windows, meaning your client won't have to learn Linux to use it, said Rand Morimoto, president and CEO of Convergent Computing (CCO), a consulting firm in Oakland, Calif. VMware and XenServer are both based on Linux, although they can host Windows guest VMs.

If your client is already using VMware or Xen for virtualization but needs to expand that deployment, it may want to consider migrating to Hyper-V, Morimoto said. Although the money your customer already spent on the other platform is a sunk cost, using Hyper-V can still save money in the long term on maintenance fees and additional licenses, he said. Your customers should balance advantages and disadvantages of Hyper-V against the additional complexity -- and cost -- of maintaining a heterogeneous virtualization environment during the transition.

CCO is part of the Hyper-V early adoption program and has been working with the platform for about four years, Morimoto said. Morimoto himself wrote a book on Windows Server 2008, and 240 of CCO's clients are using the OS in production, he said. So far this year, about a quarter of virtualization deployments CCO has worked on have used Hyper-V.

Microsoft will also provide better support for its server applications if they run on Hyper-V rather than third-party virtualization platforms, Morimoto said. If your customer is considering running applications like Exchange or SharePoint on a virtual server, support should be one of the factors in weighing the advantages and disadvantages of Hyper-V, he said.

Although several consultants said they have customers running Hyper-V in production, the fact that the product is so new may be a concern, said Michael Cherry, senior analyst at Directions on Microsoft, a Kirkland, Wash., research firm focusing on Microsoft. While the Windows Server line has been developed over several iterations and is now very solid, the fact that Hyper-V is still on version 1.0 makes it hard to predict how good it'll be, Cherry said.

The issue isn't the hypervisor as much as the platform's management tools, Cherry said. Although Microsoft is new to the virtualization market, the ideas around server virtualization are well established; VMware ESX has been around since 2001. Even if it's still too early to know all the advantages and disadvantages of Hyper-V's hypervisor, it will be thin and reliable soon enough, Cherry said.

As virtualized environments become larger and more complex, though, IT departments need good management software to track them and keep them patched and up to date. It's much easier to create a new VM than it is to set up a new physical server, so virtualized environments sometimes suffer from the creation of too many VMs, a phenomenon known as VM sprawl.

Hyper-V comes with basic management software, but more advanced systems may need the Microsoft System Center Virtual Machine Manager. Hyper-V's default management software has about a third of the features that the Virtual Machine Manager does, Morimoto said. Virtual Machine Manager can let you manage multiple VMs, making it easier to start and stop virtual servers as necessary and apply patches. It also has load balancing features, Morimoto said.

Whether your client uses virtualized servers or not, security is always a major concern in the data center. In the final installment of our Hot Spot Tutorial on Windows Server 2008, we'll look at some of its new security features and how you can use them to keep your client's data safe.