On July 28, VMware’s ESXi 3.5 hypervisor, the state of the art of hypervisors
It has been made FREE, freely downloadable and installable.
Microsoft’s Hyper-V hypervisor is available for free download on October 2nd
The Xen hypervisor, notoriously FREE in various versions, can be downloaded in the XenExpress version here
The new free version of XenServer Express 5 no longer has the limit of VMs that can be activated (4) and RAM (4GB), like the ESXi Server free and Hyper-V free versions which have no limits.
On the other hand, the issue of management tools is different, the XenCenter is free and allows from a single console to monitor and administer as many Xen hosts as we want, while the VMware Infrastructure Client can connect to only one ESX host at a time and to the Virtual Center which in version 2.5 can administer up to 200 ESX hosts, but the VC is paid (online price list 4502€), unlike Microsoft’s SystemCenter costs about 1250$ with a license per host and can administer up to 400 hosts including Hyper-V machines, ESX server machines and soon also Xen machines, as well as standard physical machines; the Hyper-V hypervisor can still be administered in a free way from the Hyper-V manager that can also be installed on Vista (but with sp1)
The HA High Availability of hypervisors is obviously not part of the free release, therefore it has a cost dependent on the Vendor’s licensing model:
VMware 2249€ for every 2 sockets (for two hosts since the cluster is made with a minimum of two physical machines)
Microsoft, you must have the Windows 2008 enterprise or datacenter license
Citrix 2200€ for each host server for the Enterprise license with XenMotion and Resource pool.
For hardware compatibility, the most open is certainly ESXi ( ESXi HCL ) which does not strictly require 64-bit processors with Intel-VT or AMD-V hardware assisted virtualization, for compatibility of installable operating systems ESXi always wins as it has its own virtualization drivers very common to almost all operating systems, allowing the installation of practically all known operating systems.
The hardware compatibility of the other hypervisors can be evaluated at the following links:
For virtual machine formats, ESXi is the only one for now to be compatible with the OVF standard while the other two are compatible with the VHD format
Let’s now analyze the structures of the licenses that can be activated:
