Choosing a Server Virtualization Platform - Part 3 (Considerations for Choosing a Virtualization Platform)
<< Part 2 - Types of Hypervisor Technology
Considerations when choosing a Virtualization Platform.
When you set about choosing a Hypervisor, you will need to look at the following parameters to reach a decision.
Various types of Guest OS’s supported.
Each hypervisor can support certain Operating Systems (OS’s). This makes sense, since each OS will work with the hardware under normal circumstances in different ways. The hypervisor needs to be built according to what OS’s are supposed to run on it.
However, other OS’s can work even on Hypervisors not specifically built for them. But predictably, if something goes wrong, you won’t get the answers and support from the Hypervisor support center that you normally will.
In addition, certain OS’s are aware of the hypervisor. These are said to have enlightened I/O. These OS’s run better on Hypervisors since they can interact with the Hypervisor in more efficient ways, essentially telling it - “Don’t worry. I know you exist as well as the problems you’re facing. I will do what’s easiest for you”.
Some OS’s that do not have enlightened I/O can be made to be enlightened with a patch from the company.
Drivers Support.
Since the Hypervisor is going to run directly on the Server Hardware and must then present a consolidated view to the guest OS’s, it must have all the necessary software to be aware of the latest underlying hardware.
Most Hypervisors support a limited set of hardware that will be exposed to the Guest OS’s, and this can be a deal breaker if your particular hardware set isn’t represented properly. Various Hypervisors take different approaches to the problem as will see in the later sections.
Interestingly, Type II Virtualizations will suffer less from this problem as they already take the hardware snapshot from the Main OS.
Speed of Guest OS.
This is a question of efficiency. How fast do guest OS’s run on the given Hypervisor? In the case of Type II Virtualizations, this will be the speed relative to the Main OS.
Ease of Management.
This aspect is already being tagged as the main differentiating factor between hypervisors. There are a plethora of issue to be managed including security, resource allocation, and Guest OS installation.
It also addresses whether or not the Hypervisor has a GUI interface, making it easy for even non-technical persons to set it up.
Another aspect of management unrelated to the above, is a technical issue as to how the Hypervisor manages the various OS’s and keeps them in separated memory spaces. That issue will be covered in in the individual review of the Hypervisors.
Support.
If you’re a business for whom downtime is costly, you will most definitely want to get a product that has commercial support. You can’t afford to play around and test what’s right and what’s not. In these cases, paying extra for professional support is a must.
On the other hand, if you want to give virtualization a whirl in a small test scenario first, you might have a lot of time to find out the details of how it works for yourself. In this case, support becomes secondary and you can focus on features that make more sense to you, like price.
