Running multiple platforms, usually VMware and Microsoft Hyper-V, is a growing trend in virtual data centers.
In TechTarget's "Virtualization Decisions 2009 Purchasing Intentions Survey," 56% of respondents said they'd prefer to avoid mixed virtual environments. But the majority said they would run multiple platforms if it helped meet a specific business need.
There are several different reasons why organizations run multiple platforms: they're migrating from one platform to another, they need an alternative platform in a specific department or branch office, or they want a different platform for a certain application. But is it a good idea to run multiple platforms?
Members of our Server Virtualization Advisory Board weighed in with their answers to this question:
What are the pros and cons of running multiple platforms for virtualization?
CJ Metz, Orange County United Way
The main reason you would want to have all your servers run on a single platform is that when it comes to training and knowledge, it's just more feasible to have a single architecture. I realize that there are tools like Microsoft's System Center, which can integrate with both Hyper-V and VMware, but this comes at an added cost.
As for why we might want multiple vendors, in the event that one virtualization vendor puts out a patch that crashes our servers, we can be safe in knowing that not our entire environment runs on that architecture. Another good reason to have a hybrid environment is that certain virtualization vendors have pros and cons. For example, we might be interested in having VMware's more expensive High-Availability and Distributed Resource Scheduler for core production servers, and we might want lower-priority systems to run on lower-cost Hyper-V servers.
Eric Siebert, Boston Market
While it is common to see mixed environments of operating systems and applications, I honestly feel that most data centers are not going to see a mix of virtualization platforms inside them. The virtualization layer is closer to the hardware layer, and most shops stick with a single hardware vendor for all their servers. Consequently I only think there are cons to doing this, such as:
- Management: Different hypervisors require completely separate consoles, management applications and support software in most cases. Microsoft System Center claims to support VMware ESX, but only in a limited manner and not very effectively.
- Training and expertise: Getting training and gaining expertise in different hypervisors requires double the time, effort and expense.
- Interoperability: Most hypervisors do not use the same formats for virtual machines. Therefore, moving a VM from a Hyper-V server to an ESX server requires extra steps, as well as downtime for the VM.
More cross-platform management tools, as well as a common virtual disk format, would make mixed hypervisor environments much more feasible. But I see most companies sticking with whatever hypervisor works for them and not using any others.
Shannon Snowden, New Age Technologies
My experience has been that if you know one hypervisor, then you can pick up the other ones very quickly, because you just have to find how each one accomplishes essentially the same task. So I don't mind mixing them, if that is what the client wants to do.
However, when mixing vendors, you do introduce the inefficiency of different VM formats. If that is an issue you don't want to deal with, stick with one vendor and tier your virtual infrastructure with different versions of that vendor's hypervisor. You can put critical production virtual machines on your best hardware, with the enterprise fault-tolerant feature set, and put your test and lab machines on the free or cheaper versions of the same product.
Dave Sobel, Evolve Technologies
Mixed environments have the advantage of offering the best of both worlds in terms of features. Features available on only one platform become something you can leverage, and you can link workloads to the appropriate environment. For example, a Microsoft-based platform can be placed entirely within a Microsoft virtualization system, and Linux environments (not supported by Hyper-V) could be placed on VMware.
The downside is that moving from one platform to another requires conversions, and you are maintaining support relationships with two vendors. Management tools become more complicated, because they must support both virtualization platforms. Support staff will need to be certified on both environments, and support contracts must be available on both platforms. This added complexity and cost can be justified based on business need, but it's important to understand those needs first!
Have a question for the Server Virtualization Advisory Board? Email Colin Steele, Site Editor.