When comparing Type 2 Hypervisor vs Type 1 Hypervisor, the Slant community recommends Type 1 Hypervisor for most people. In the question“What are the best approaches to OS virtualization?” Type 1 Hypervisor is ranked 3rd while Type 2 Hypervisor is ranked 5th. The most important reason people chose Type 1 Hypervisor is:
Hypervisors can emulate hardware separately for each host allowing them to run multiple operating systems.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Ease of use
By running on hosts operating system, type-2 hypervisors can be installed and set up the same way any other software is installed.
Pro Lots of flexibilty of what hypervisors on what OSs are run
Hosts hardware can run multiple OSs and multiple type-2 hypervisors can be run side by side on each of the operating systems.
Pro Can run multiple operating systems
Hypervisors can emulate hardware separately for each host allowing them to run multiple operating systems.
Pro Can run multiple operating systems
Hypervisors can emulate hardware separately for each host allowing them to run multiple operating systems.
Cons
Con Very high overhead
Very low density, performance, scalability. Additional performance hit from OS layer.
Con Considerable overhead
Depending on the host hypervisor may take up anywhere from 3% of the hosts memory and cpu resources up to 35%.
Low density, performance, scalability. While some issues are mitigated with new hardware features such as VT-D, the overhead is considerable.
In certain specialized cases many of these issues can be sidestepped via the use of unikernels. Unikernels are specialized, lightweight operating systems for hypervisors. They are built to run only the necessary processes with only the necessary parts of necessary libraries in order to vastly increase performance. They reduce the memory footprint, the need for disk space and computational burden. Additionally they further reduce the attack surface.