Computers never last as long as we think they should. Disk drives fail, processors overheat, and the capacitors in memory chips slowly fade away. Wintel servers bought in the mid-90s are coming to the end of their natural lives. Unfortunately, they're often still running critical line of business applications, on operating systems that can't handle the latest hardware, can no longer be bought and are no longer supported.
So what's the solution? One option is to take advantage of virtual server technologies. Not only do they offer savings by consolidating systems and extending application life cycles, they can also reduce support costs and speed up new system development.
With desktop virtual machines anyone can run a second operating system on their PC without rebooting. Now a new generation of more complex virtual servers means that one modern server can host multiple operating systems, running them at the same time - along with the applications that used to run on the separate machines. With virtual servers there is less hardware in the data centre, keeping down costs.
Microsoft's purchase of Connectix's Virtual PC technology - along with the development team - will add virtual machine technology to Windows. The original Virtual PC ran Windows inside Apple's Macintosh OS. Virtual Server, now in beta, runs multiple operating systems, including various Windows versions, Linux and OS/2, all at the same time on the latest PC server hardware. Microsoft intends to use Virtual Server to support companies still needing to use older versions of Windows as they migrate to newer technologies.
Despite a flurry of recent interest, virtual machines are not really a new technology. They've been at the heart of IBM's mainframes for many years, so it's hardly surprising that IBM engineers have come up with an alternative approach to the virtual server. IBM offers the zSeries mainframe configured to host a set of virtual Linux servers.
IBM has ported the Linux version of its WebSphere J2EE platform to its mainframe Linux offering, so it can deliver complex applications on a familiar application server. As mainframes are a considerable investment, IBM offers a virtual server hosting facility, running your applications on IBM's own Linux mainframe server farm. Even your virtual server can be virtual!
Commercial virtual servers don't have the market all to themselves. Open source solutions, like the Bochs project, are already hosting Windows NT images on Linux servers, using the X Window environment. Expect support for more operating systems in the future.
Virtual servers don't only consolidate legacy systems, they also keep complex applications isolated, while still running them on a single server. It's always been good practice to put different applications on different machines, for high reliability and availability. Virtual servers give the same benefits by keeping each application in a separate operating system image; if anything goes wrong, all an administrator needs to do is restart the appropriate virtual machine, without affecting the rest of the applications and operating system images running on the same hardware.
Support staff will find virtual servers helpful too. Instead of having to support multiple-server operating system and driver images, all they need to have is a single base configuration, along with the appropriate operating system images. As these work on any hardware that runs a compatible virtual machine, they can deploy the images as and when they are needed. Rolling out a new server is as easy as copying a file.
It's not only existing enterprise applications that benefit from the virtual servers. Deploying operating system images to virtual servers running on developers' PCs speeds up development. Sharing centrally created server images means each developer is working on the same snapshot of the system, without needing expensive test rigs.
Used carefully, virtual servers look likely to become an important element of enterprise architectures. With virtual servers, an organisation can move forward, without leaving the past behind.
