Ship dates for Microsoft Virtual Server have slipped of late, with the first beta only released this February, a year after the acquisition of developer Connectix. However, that’s good news for virtualisation market leader VMWare, itself acquired recently by storage giant EMC, although the company isn’t resting on its laurels. Indeed even if the ship date is only a coincidence, the February launch of its updated mid-range server product, GSX Server 3, has enabled it to steal much of Microsoft’s virtual thunder.

As with previous releases, GSX Server version 3 enables multiple operating system partitions to be run concurrently on industry standard x86 hosts. The processors can be from AMD and other vendors, not just Intel, and privately the company admits to also having a 64-bit Itanium implementation in test. However, there are no plans to bring this to market, at least not this year. Neither can you deploy the current GSX Server on AMD processors running in 64-bit mode although that too could change, and support for the new 64-bit Xeons is bound to be added.

To deploy GSX Server you need both a hardware platform and a host operating system, on which the VMware software is setup and run like an ordinary application. Guest operating systems are then installed on top, each instance becoming a totally separate virtual machine (VM) running its own applications in an isolated partition.

Each VM can be booted, edited and changed independently and, unlike the upcoming Microsoft product, the host operating system can be either Windows (Windows 2000 Server or Server 2003) or Linux, with an enhanced number of guest operating systems supported in the new release. Among these all versions of Windows up to Server 2003 are supported, including MSCS clusters, along with pre-release versions of the forthcoming Longhorn implementation in, so-called, experimental mode.

Enterprise versions of Red Hat and SuSE Linux can also be run as guests along with FreeBSD and other implementations, with support too for the latest 2.6 kernel. NetWare 6.5 can also be run as a guest.

VMWare provides true hardware virtualisation, with each VM able to access the processors, memory, storage, networking and peripherals on the host system as if no other VM were running. Scalable SMP servers with up to 32 processors can be used with the amount of memory each VM can be allocated increased from 1.2GB to 3.6GB in the new version.

Almost any device supported by the host operating system can be made available to a VM including ATA and SCSI storage with support for SCSI backup tape drives now also provided. Another plus is the ability to both bridge virtual LAN interfaces directly to physical network adapter ports or define up to nine virtual Ethernet switches. The latter approach makes for fast communication between guest partitions while for external networking there’s new support for teamed network adapters and PXE provisioning.

Of course, with so much functionality on offer you might well expect the VMware product to be difficult to get to grips with, but installation is no harder than for any other Windows or Linux application. Moreover, each virtual machine is configured and stored in single image file such that it takes just a few minutes to bring a new VM online or move it to a different host. Point in time snapshots can also be taken of running virtual machine states while a new browser-based GUI with a built-in remote console is another bonus in this release. Added to which there’s full integration with VMware VirtualCenter to provide better central control over provisioning and customisation, across multiple hosts.

New too in this release is integration with test solutions such as IBM Rational TestManager which will be a boon for the many developers using VMWare to try out their code. Added to which companies starting with GSX Server can now migrate virtual machines to the ESX Server platform, rather than having to rebuild them from scratch. A datacentre class product, ESX server doesn’t require an existing host operating system, making it more scalable plus it offers enhanced fault isolation and real-time failover facilities.

On the performance front VMWare has managed to squeeze out a 10-20 per cent increase in disk and networking capabilities in GSX Server 3, which is good for companies looking to use the software for server consolidation. It also puts more pressure on Microsoft to get its Virtual Server product to market, with June/July now the most likely timeframe for that release.

Finally it’s worth noting that Microsoft is marketing its virtual server more as a Windows migration tool than as a platform for use by developers or for production server consolidation. Naturally that could change as the product matures, but in the meantime it leaves VMWare as very much the market leader in this market with GSX Server 3 adding further to its product armoury.


GSX Server addresses the needs of two types of customer. Developers wanting to test their applications and medium-sized companies looking to consolidate server hardware. The latest release is of value to both with test tool integration for developers, together with performance and functionality improvements for consolidators. Both can save time and money with this release although for large deployments the more scalable ESX Server might be a better investment. A much cheaper Workstation package is also available for individual developers.