The advantages to simplification in enterprise IT are well known, making life easier from the point of view of security, regulatory compliance, end-user support, and just about every other group or function you can think of. In many instances these advantages outweigh any concerns and justify reducing product count in servers, desktop environments, smartphones, and the glue that holds them all together. Yet for all those obvious advantages, there are situations in which multiple vendors and multiple products make a lot of sense. One of those situations is in hypervisor management deployment – a situation that many people think cries out for a single enterprise solution. In fact, though, the different requirements for hypervisors in different deployments may make a multi-vendor strategy the most intelligent option for many organizations.
Look first at what hypervisors do. In virtual server and storage applications, they create, manage, and tear down virtual-server instances. Managing memory, CPU, and other facilities within the physical server for the use of multiple virtual servers is the prime task set for the virtual server hypervisor. The hypervisor is all about what's going on within the virtual machines – there's no real architectural accounting for jobs to be split between the virtual server and whatever clients might exist for the applications running on the server.
That idea of split responsibility is at the center of the virtual desktop world. The big issue is whether the graphics of the desktop are rendered on the server and downloaded in compressed form as images to the client, or are rendered on the client based on instructions sent from the server. The difference for the IT department is just how much horsepower the client needs in order to render the graphics in the second scenario. That horsepower difference could have a huge impact on total rollout costs if client purchases are included in the calculations.
If the plan for virtual desktops is to use an existing, current-generation desktop or laptop computer to display the virtual desktop, then really just about any hypervisor will do. Any of the choices you might make will happily serve commands to the clients. It's important to note that all the choices provide the security, the consistent user experience, the central control, and the ultimate desktop control and manageability typical of the virtual desktop experience. If, on the other hand, you need to make the most of a wide variety of physical end-points on which to provide a common virtual desktop, then the story changes dramatically.
Only one hypervisor provides rendering on the server, allowing the most complete use of lightweight endpoint devices. As of this writing, Microsoft's® Hyper-V is the only hypervisor that renders on the server, leaving only the lightest duties to the client. And right there you have the case for multi-vendor hypervisor deployment.
A compelling case can be made for deploying Microsoft Hyper-V, Citrix XenServer, or VMware ESX as the enterprise solution for server virtualization. Each has strengths and weaknesses, as well as specific use cases in which it will shine. If the corporate decision is for Citrix or VMware on the server, and the need exists for the thinnest possible devices on the virtualized desktop end of things, then the right answer is multi-vendor.
For more information, see:
Server Consolidation With Virtualization
Storage Virtualization
Desktop Virtualization
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