There are a plethora of virtualization software tools on the market. Some are quite affordable, even free, while others are very expensive, enterprise-level software solutions. To decide which one you need, you should first ask yourself why you need virtualization.
If you are using virtualization for testing, you probably do not need buy an expensive product with management features you will never use. Something simple and free may be enough.
For full server virtualization in long-term production environments, you will need something robust, designed to stand up to the harsh weather of the Internet, while also not taxing your server’s hardware. Moreover, if you need virtualization for a specific task, such as hosting a virtual private servers (VPS), it is best to choose a package designed with that purpose in mind.
Virtualbox – Good for testing environments, open source, and easy to use.
KVM – Linux kernel-based virtual machine. With a built-in kernel module, it is supported by most Linux distributions
Xen – A hypervisor virtualization software, useful for running long-term virtualized environments
VMware – One of the most popular — offers both small business and enterprise versions
Oracle VM – Based on Xen technology
Microsoft Hyper-V – For Windows hosts only but supports numerous guest OSes
Parallels Server – Windows, Mac, Linux, and Bare Metal hosts
VPS (Virtual Private Server)
Parallels Virtuozzo – commercial VPS software
OpenVZ – free and open source Virtuozzo competitor