Virtual servers have become a must have for companies that are starting up or trying to cut back their budget. Being able to cut back by turning one dedicated server into several smaller ones can be a great boon, but there are some important choices that you will have to make. You need a specific type of virtualisation software to implement the new structure and there are a lot out there. Unfortunately, this makes it difficult to choose, because of budget or configurability. A few of the most popular virtualisation platforms available are OpenVZ, Xen and KVM; but it is up to you to decide which is best for your company.
Type One Hypervisors
Hypervisors, also known as virtual machine managers, are one of the primary techniques used to allow multiple operating systems to run at the same time on a computer network. A type-1, or bare metal, hypervisor is at type that runs directly on the system’s hardware. This kind of virtualisation has been in development since the 1960’s and thanks to being directly on the hardware, it is much easier to implement and manage because it is not added software; it is part of the system. However, it is much more difficult to coax out as much performance as with type-2 hypervisors. The kernel-based virtual machine (KVM) is an excellent example of the newer class of bare metal hypervisors.
Type Two Hypervisors
Type-2 hypervisors are also known as host hypervisors and run within the actual operating system. This creates an extra level within the system structure that is more complicated to manage and requires heavier usage of resources within the network. Xen is one of the best examples of a host hypervisor and while it does use more resources within a system it is also more flexible and allows for greater performance. Unlike KVM, which can only run on Linux, it can run on multiple platforms such as Windows or FreeBSD.
There are many programs out there that operate beyond the hypervisors, like OpenVZ. These programs do not offer true virtualisation; they create containers for each operating system instead. OpenVZ does not have as much customisability as programs like Xen or even KVM, but it does still work very efficiently on small networks, is easy to manage and is also much cheaper.
All of these can be very good choices depending on what you need. KVM is definitely the most stable and resource-lite option, but it does not get the same functionality and performance boosts that you can find in Xen. And if your network is relatively small, you can save a lot of money by using OpenVZ. The final decision is ultimately yours, so choose wisely and find the right virtualisation software for your business.