Last week on July 12th VMware finally released their VMware Server product. This product, formerly know as GSX, has been available in a beta version for some time know.

This is an exciting release! VMware Server is VMware’s competition to the Microsoft Virtual Server. VMware Server and Microsoft Virtual Server are both considered hosted applications. This is different from VMware’s ESX server which is considered a “bare metal” installation.

What this means it that VMware Server and MS Virtual Server are applications that install on top of an operating system. VMware ESX installs directly on the hardware and acts as a combined operating system / application.

This is a simple VMware Server architecural diagram. This diagram works to illistrate the basic archiecture of both VMware Server and MS Virtaul Server. Notice, that the virtualization application (in this case VMware Server) sits on top of a Windows or Linux Operating System. Everytime one of those virtual machines on top need access to resources, it must resquest them from the the application which inturn must request them from the operating system. That operating system is not specifically optimized to handle this type of work load. As a result, VMware Server or MS Virtual Server must compete with the other applications that are running on this machine. (You should note that whereas VMware Server runs on either Windows or Linux, MS Virtual Server only runs on Windows.)

Compare the previous image with ESX’s architecure. Notice that there is no “Operating System” layer. That’s because ESX is the operating system and application in one. The VMkernel manages all resourses and is optimized to do nothing but virtualize hardware. This means that resourse are more readily available to the virtual machines being hosted.

So why run a hosted application like VMware Server? Well, for a start it’s free (as long as you don’t require support). This makes it easier for testing and developing applications. It’s also good for lower end applications, or admins to get their feet wet with the whole concept of virtualization. Download it and give it a try!

You can read the official announcement here.

I’ll make sure to do a VMware Server Vs. MS Virtual Server post soon!