Hypervisor Options
In today’s server environment, hardware has by far outpaced what is needed for the majority of applications. On top of that, running an OS as a virtual guest will allow for easier backups and disaster recovery. There are two levels of virtualization, operating system level and full virtualization. Full virtualization in the server environment is primarily type-1 or bare-metal hypervisors. Type-2 hypervisors are utilized on workstations. There are also some hypervisors that can be classified as either type-1 or type-2.
While most type-1 hypervisors perform the same task, they are not all created equal. One of the most popular type-1 hypervisor is VMware vSphere. The user interface of vSphere has recently moved to an html-5 based interface, which while convenient, does not always behave as expected depending on the browser used. VMware also has a disk latency issue that can cause issues with certain use cases. VMware does offer some of the best integrated management, and it can also interface with other VMware products. The VMware guest support is also very helpful and provides additional control from the host. However, many vSphere features require additional licenses.
XenServer is an open source solution that is also available slightly customized from different vendors, providing you with a better user interface. Citrix is a popular option, and can provide consistency throughout the environment if other Citrix applications are in use. The control interface from Citrix, XenCenter, is resource intensive, especially with extra module added. As hardware progresses, the impact of the resource utilization has shrunk.
Microsoft Hyper-V requires a Windows Server, but you can run it in “core mode” allowing lower resource use by the server OS, and also risk from vulnerabilities, as only the minimal services will be used. Hyper-V has some advanced features that are only available for Windows guest, however if the intention is to virtualize only Windows servers, Hyper-V is a great option.
KVM is an open source hypervisor that runs on top of Linux. Due to the open source nature, many different options are available for GUI management. It has been merged into the Linux kernel, and performance is excellent if built correctly. Unfortunately, since it does run on top of a Linux host, there is temptation to use other processes on the base OS. This should be highly discouraged, as it will impact performance.