Friday, April 17, 2009

The difference between the Microsoft’s Hyper-V and the VMware’s ESX hypervisor

Greg Shields published an interesting article that explains the difference between the hypervisors of Microsoft’s Hyper-V and VMware’s ESX. It is a response to a widespread misunderstanding. VMware supporters tend to believe that VMware ESX has a bare metal hypervisor, whereas Hyper-V runs like Microsoft Virtual Server 2005 on top of Windows. Greg explains in detail in what sense both virtualization solutions are Type 1 hypervisors contrary to Virtual Server and VMware Server, which use Type 2 hypervisors. A Type 2 hypervisor is installed on top of the administrative OS, whereas a Type 1 hypervisor runs on bare metal, a layer below the administrative OS (Windows Server 2008 in the case of Hyper-V and Red Hat in the case of ESX).

However, there are also important differences between Hyper-V’s and ESX’s hypervisors. Greg makes things absolutely clear: Hyper-V has a far more advanced hypervisor because it is microkernalized, whereas ESX has a monolithic hypervisor. Among other things this means that Hyper-V uses synthetic device drivers, which are just pointers to the real device drivers into the primary partition’s administrative OS (Windows Server 2008). ESX’s device drivers exist within its hypervisor.

Source : 4sysops