Virtualization

Understand the differences between VMware's Workstation, GSX, and ESX

Virtual machines appear to be part of the next wave of server-based computing, and VMware remains the leading provider of this technology. Learn the distinctions between VMware's Workstation, GSX Server, and ESX Server products.


VMware Workstation and its virtual computing technology have changed the way most companies look at test environments, and in some cases, even production environments. However VMware Workstation isn’t the only technology that VMware has to offer. The company also offers GSX Server and now ESX Server as well. Let's look at how to best leverage these technologies in your company.

VMware Workstation
VMware Workstation uses virtual machine technology that is designed mostly for the power user. It allows you to run multiple operating systems on a single PC. The operating systems that can run under a VMware virtual machine can include Windows 2000, Windows XP, Windows 2003 Server, Novell Netware, and Linux.

After running through a simple installation of VMware Workstation, you have the ability to configure virtual machines within VMware’s interface. These virtual machines act and look just like a real computer, except they sit inside a window (Figure A).

Figure A


In addition, you can network these computers, join and disjoin them from a domain, connect to the Internet and other networks from within them, and simulate whatever environment you choose.

On one of my computers, I've used VMware Workstation to simulate an entire Windows 2003 network with Windows XP clients. With this environment, I can test all of the Windows 2003 product line for compatibility with my network, as well as study for my Windows Server 2003 certification exams. In the past, I had to have at least three systems to be able to accomplish this kind of testing. Now all I need is one computer, an Internet connection, and VMware Workstation.

How does this work?
VMware works simultaneously with your operating system to allow you to host multiple virtual machines. It does this by allowing you to configure your virtual machines on the VMware virtualization layer. This layer lets you map your hardware to the virtual machine's resources and have virtual machines mapped to your floppy drive, hard drive, CPU, etc. Inside each virtual machine, you can create virtual hard disks and specify how much RAM you want to allocate to each of your virtual machines. Plus, each virtual machine can have its own IP address, even if the system hardware has only one network adapter.

In most of the environments I've seen, VMware Workstation is typically used to configure test environments, software development testing, training classrooms, and technical support (to simulate the environment of the user). Now that you've seen how the power user can use VMware, let’s examine how VMware can meet the enterprise server and mainframe needs of your company.

VMware GSX Server
I recently was given the opportunity to evaluate VMware GSX Server, and I was impressed by how well it worked. VMware Workstation supports only one CPU and up to 1 GB of RAM. GSX Server supports 2 CPUs and up to 2 GB of RAM. GSX Server is very similar to Workstation in most other ways, but one of its coolest features is the Remote Console that allows you to remotely manage and access your virtual machine from anywhere on your network. In addition, it's much easier to work with in a high availability configuration.

While VMware Workstation is mostly used by a single user to run multiple instances of operating systems for testing and support purposes, GSX Server is often used for server consolidation by running virtual machines of server operating systems that simply appear to be stand-alone servers to clients on the network.

VMware ESX Server
VMware ESX Server is mainframe-class virtual machine software. This solution is typically used by mainframe data centers and cutting-edge companies. I've also seen this solution used by startup companies. With ESX Server, you can do amazing things such as more extensive server consolidation and virtual machine clustering.

How does it differ from GSX Server and VMware Workstation?
With VMware Workstation and GSX Server, the software sits on top of a host operating system such as Windows or Linux. With ESX Server, the software runs directly on the system's hardware, eliminating the need to install a base OS. In fact, ESX has its own OS. The software basically runs on its own Linux kernel, and Linux is quite beneficial to know when working with the product, although it's not an absolute necessity.

Installation of this product is quite basic. You place the CD in the tray of a system and boot from the CD. It runs you through a typical Linux installation. At the end of the install, you're instructed to go to a separate machine and type in a specific Web address to access the virtual console of ESX Server. From there, you'll configure your system and create virtual machines. With ESX Server, you can have up to 3.6 GB of RAM per virtual machine as well as high performance network cards.

How are companies using ESX Server?
What I really like about this product is how companies are using it. For example, I've seen startups simply purchase a SAN and ESX Server and create their whole network using ESX Server. This includes the servers and workstations, which are accessed with thin clients.

GSX Server is lightning fast, so you can’t tell the difference between real systems and its virtual systems (if you have powerful hardware running GSX Server). Furthermore, I've seen data centers use ESX Server for hosting client environments and test environments. In the future, I think more companies will take advantage of ESX Server as part of their business strategy.

Final analysis
Virtual machine technology is becoming more and more mainstream in today’s IT marketplace. With the current trend toward consolidating servers, VMware is quickly making a place for its products in the server room. Microsoft has even taken an interest in the virtual machine market by buying Virtual PC. However, Microsoft's product line doesn’t quite have the maturity of the VMware product line when it comes to providing enterprise-class server solutions.

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