Best free bare metal virtualization software

Bare metal virtualization software runs directly on the host's hardware as a hardware control and guest operating system monitor. You don't need an OS to run on the host hardware. This software is great for running multiple OS environments on a single physical host. You can consolidate your data center by cutting down on the number of physical machines and conserve energy. Get with the green program folks!

I looked at 3 of the free bare metal hypervisors in the market:

• VMWare ESXi
• Citrix Xenserver
• Oracle VM

VMWare ESXi does not give you centralized management abilities for free. You need to purchase additional tools from VMWare to get this ability. Citrix and Oracle provide centralized management and many other features that are not available with VMWare for free. Oracle is still not very popular in the baremetal hypervisor market and needs to gain a lot of ground.

I personally found Citrix Xenserver to be the best among the available baremetal hypervisors for the following reasons:

1. A wide array of features required to run your servers available free of cost.
2. Max support of 8 virtual CPUs vs. only 4 for ESXi
   
3. Better hardware support for SATA harddrives out of the box [ESXi only supports SAS/SCSI - you need to hack it to make it work with SATA].

It remains to be seen how long VMWare will sit back and let Citrix gain some ground before leveling the playing field by introducing free features in their product.

There are some hardware requirements for these hypervisors. You need to have 64 bit CPUs that support either the Intel-VT or AMD-V hardware virtualization technology. There is also a very limited subset of hardware that these hypervisors are certified with. Make sure to check these requirements before making the jump into bare metal virtualization. The alternative is to go with a hosted hypervisor [a.k.a Type 2 hypervisor] such as Sun's Virtualbox, VMWare Server, or Microsoft VirtualServer.