I hear this question occasionally. I hear the usual because it’s free or because it’s secure. While all of this is true and certainly plays a part in the decision to use Linux it is not my primary reason for using Linux.
In a nutshell it comes down to a substantially better price:performance ratio. Take for example Red Hat’s virtualization product. For starters Red Hat integrates their virtualization product into the operating system at no additional cost. The real kicker though is the performance when compared to VMWare.
Red Hat and Intel worked together to produce a tightly integrated virtualization package with the Caneland processor. Having completed the project they asked independent laboratory Principled Technologies to perform some industry-standard benchmarks on these new capabilities. The results can be found here
In their tests they used a Red Hat 3 stand alone server, a Red Hat 5 server and another Red Hat 3 server virtualized on the RH5 machine. The results are as follows:
* A Xeon system running Red Hat Enterprise Linux 3 achieved approximately 210,000 operations/second (4 socket, hyperthreaded, dual core allowing for 16 compute threads).
* A Caneland system running Red Hat Enterprise Linux 5 achieved approximately 380,000 operations/second (4 socket, quad core also allowing for 16 compute threads).
* A Red Hat Enterprise Linux 3 virtualized guest running on a Red Hat Enterprise Linux 5 host achieved approximately 340,000 operations/second. So Red Hat Enterprise Linux 3 delivered a performance increase of over 50 percent when running virtualized on the new Caneland system.
Regarding virtualization on VMWare there are some points to consider. The first is quite simply the added cost of VMWare regardless of what operation system is your choice. Regarding virtualization Red Hat Enterprise Linux guests can utilize all the underlying hardware – so a full quad-core, 4-socket system can be virtualized and presented to Red Hat Enterprise Linux 3. VMWare does not support guests with more than 4 executable threads. What that means is that VMware cannot provide a virtual machine guest larger than 1/4 of the new Caneland capacity.
Although I discussed only one technology there are many examples to be found. And when I hear of places such as Indiana University with almost 200,000 faculty and staff, Amerada Hess Corporation – Oil Exploration Supercomputing, Burlington Coat Factory – Entire Systems, Conoco – Oil Exploration Supercomputing I have to believe that these folks have some very smart engineers and CTOs on their IT staff that would decide that Linux is the best platform on which to be running. The complete list can be found here.