Even though choosing a hypervisor is only a small part of implementing a virtualisation strategy, much has been written about how Microsoft Hyper-V compares to VMware ESX – and there are some fundamental differences between those two products. Architecturally, Hyper-V has a lot more in common with the Xen hypervisor (although they are not identical) and indeed XenSource worked with Microsoft to provide Linux support for Hyper-V and I’ve recently been alerted to the presence of a short white paper which compares Hyper-V and the Xen technology implemented in Red Hat Enterprise Linux (the leading Linux distribution, which is not currently on the list of supported guest operating systems for Hyper-V). Despite being published by Microsoft, it seems to me to give a balanced view between the two products, although it should also be noted that Red Hat has announced it will be switching from Xen to KVM for future virtualisation support.