Virtual machine (VM) software has earned a place in the development and test beds of many organizations because of the ease with which it lets you create multiple test environments without having to set up different physical systems for each environment. The improvements that VMware has made to the latest versions of its VMware GSX Server show that VM solutions can effectively test production-level server consolidation. VMware designed VMware GSX Server 2.5 for enterprises that want to consolidate multiple virtual servers on one high-end Intel-based system. VMware GSX Server supports as many as 64 VMs running on systems with as many as 32 processors and 64GB of RAM.

You install VMware GSX Server after installing the base OS. The product works by implementing a software layer called the VM that emulates the hardware. You then install an OS known as a guest on each VM. Guest OSs can run concurrently, as if each were running on separate systems. Each VM has its own virtual hardware, including a processor, a hard disk, memory, and network devices. VMware GSX Server handles the task of "virtualizing" the real hardware and sharing it with all running VMs, and can also use a virtual network to connect the VMs—a feature that gives all the VMs access to your network resources.

VMware GSX Server requires a minimum of 256MB of RAM, plus enough additional RAM to run each guest OS. The product supports a maximum of 64GB of RAM running on Windows-based hosts. VMware GSX Server requires 275MB of hard disk space for the VM server, the VMware Management Interface, the VMPerl API, and the VMware Remote Console. In addition, VMware recommends that you maintain 1GB of hard disk space for each VM you install.

You can install VMware GSX Server on host systems running Windows Server 2003 Datacenter Edition, Windows 2003 Enterprise Edition, Windows 2003 Standard Edition, Windows 2000 Datacenter Server, Windows 2000 Advanced Server (Win2K AS), Win2K Server, and Windows NT Server 4.0. For guest OSs, VMware GSX Server supports most Microsoft Windows desktop and server OSs, several Linux distributions, and even Novell NetWare. Because each OS runs independently, you need separate licenses for each guest OS. Table 1 lists all the guest OSs that VMware GSX Server 2.5 supports.

VMware provides a virtual system platform for each VM. The VM thinks it's running on a one-processor system with an Intel 440BX motherboard using the NS338 SIO chipset and Phoenix BIOS 4.0 release 6.0. Depending on the system's capacity, you can allocate up to 2GB of RAM per VM. Each VM sees an SVGA graphics card, can have as many as four IDE drives of 128GB, as many as 14 SCSI devices on two virtual SCSI controllers, as many as two 3.5" disk drives, four serial ports, two parallel ports, two 1.1 USB ports, three virtual Ethernet cards, and a virtual mouse and keyboard.

Virtually Up and Running
I installed VMware GSX Server on a dual-processor Hewlett-Packard HP NetServer system with 1GB of RAM. The product's CD-ROM doesn't include an autorun file, but the VMware GSX Server installation was easy nevertheless. I simply navigated to the CD-ROM's Windows directory and ran the vmware-gsx-server-installer-2.5.0-3986.exe program. After I entered the 25-digit serial number and read the installation screens, I had VMware GSX Server running within a few minutes. The only notable occurrence was that the setup program informed me it was turning off the system's CD-ROM autoplay feature to prevent possible hardware conflicts.

After I installed the product, I was ready to create a VM. VMware GSX Server asks you what guest OS you intend to run on the VM, then prompts you to name it and, optionally, allocate a custom amount of memory to it. Figure 1 shows the New Virtual Machine Wizard that you use to create a new VM.

When you select the Virtual Disk option, VMware GSX Server creates each VM in an isolated data file with a .vmdk extension. This feature lets you save virtual disk files to tape or disk to archive VMs or easily move files among VMware servers. You also have the option to create the virtual disks as persistent, nonpersistent, and undoable disks. The persistent option lets the virtual disk behave as if it were a standard disk. When you select this option, the system preserves all modifications you make to the disk when you stop and restart the VM. The nonpersistent option directs the system to discard any changes you make to the VM when you power it off, which can be handy when you want to ensure that you always start with the system in a known state. The undoable mode lets you choose to keep or discard system-state changes when you turn off a VM.

After creating a VM, I used the VMware GSX Server console to power on the VM. The server then opened a window on the host server that prompted me to install the guest OS. I inserted the Windows 2003 CD-ROM, and the standard Windows installation process began and progressed as if I were installing the software on a standalone system. I restarted the VM after the installation finished, and the guest OS was up and running.

After you install the guest OS, you should install the VMware Tools on the guest OS. The guest OS can run without the VMware Tools, but they provide some important enhancements to the functionality of the VM, including enhanced SVGA video performance. In addition, the VMware Tools control panel lets you synchronize the time between the VM and the host and resize the virtual disk. The utilities let you copy information among VMs and provide a set of scripts that you can configure to automatically run when the VM state changes.

I found performance to be surprisingly good with a few active VMs, but as you might expect, performance degraded as I made more VMs active. The total available memory limited the number of VMs that I could have active simultaneously. Performance depends a lot on the total RAM available in the system and the functions you perform with each VM.

An included suite of management tools makes configuring VMware GSX Server a snap. For local management, VMware GSX Server provides the VMware GSX Server management console, which runs directly on the host system. The local VMware GSX Server management console lets you create, monitor, start, stop, reset, and suspend VMs. It also lets you run the VM in full-screen mode, in which a VM appears as if it's a standalone system. Running the VM in full-screen mode also provides a noticeable performance improvement because this mode provides exclusive access to the VM. A strength of VMware GSX Server is that you can manage it remotely using either its browser-based VMware Management Interface or the Remote Console. The VMware Management Interface is a zero-footprint management tool, and it connects to the virtual server through http//<host>:8222. The Remote Console, which you install on a networked PC from the client installation section of the VMware GSX Server CD-ROM, is similar to Win2K Server Terminal Services in that it prompts you for the name of the host server, then displays a management window that lets you perform the same tasks you can perform from the local VMware GSX Server management console. Note that you can't use the Remote Console while using the local VMware GSX Server management console to manage a VM. Figure 2 shows the GSX Server Remote Console in Suspended mode.

In addition to the Remote Console, VMware GXS Server gives you a VmCOM Scripting API and a VmPerl Scripting API that you can use to control the virtual server. Both scripting APIs offer similar functionality, letting you write scripts that automate virtual server management tasks. Unfortunately, you must visit the VMware Web site at to access the documentation for these APIs.

The documentation that accompanies VMware GSX Server is outstanding. The 550-page user's manual thoroughly describes the Windows and Linux installation procedures and offers detailed instructions about performance tuning and setting up Microsoft Cluster service with VMware GSX Server. I didn't encounter any problems during the review, so I never needed to use the company's technical support line. However, while learning how to use and set up the product, I did find valuable information both on the support Web site at as well as in the VMware newsgroups at vmware.gsx-server-for-windows and vmware.guest.windows2000.

VMware GSX Server pricing starts at $3035 for a two-processor system and $6050 for a four-processor system, making this product competitively priced with other VM offerings. VMware GSX Server's new features make it a good choice for an organization that's looking to consolidate its server environment. The improved scalability and easy remote management capabilities make VMware GSX Server an effective solution for simplifying server management and reducing the number of systems required to support an organization. If you're not already using a VM solution in your test environment, you should definitely look into the flexibility of creating the multiple test scenarios that VM products enable. For information about additional VM offerings, see the sidebar "Other VM Products," page 36.

VMware GSX Server 2.5
Contact: VMware * 650-475-5000
Price: Starts at $3035 for a two-processor system
and $6050 for a four-processor system
Decision Summary
·Easy to use
·Flexible management options
·Excellent range of support for
multiple guest and host OSs

Cons: Noticeable performance lag when multiple VMs are active