Linux gains virtual momentum

The race is on to add server virtualisation tools to enterprise versions of Linux, such as Red Hat Enterprise Server and Novell Open Enterprise Server, both updated in early February.

Red Hat and Novell will not add server virtualisation tools to the current versions of their enterprise Linux server products, but are working to include them in the next versions, due in about 12 months.

Server virtualisation tools enable a single server to run multiple operating systems. They also improve server management - for example, by enabling systems to be backed up or moved to new hardware without shutting them down or interrupting services. Experts predict that within five years 95 percent of Wintel server deployments will use virtualised hardware. With at least three open-source server virtualisation projects under way, the developer community already seems convinced about the usefulness of such tools. And Open-source giant Novell has promised "significant announcements" about open-source server virtualisation.

Also, Red Hat's Fedora Linux distribution already supports Cambridge University's Xen open-source virtual machine monitor (VMM) tool; and Microsoft launched its Virtual Server 2005 late last year. Red Hat spokesman Nick Carr said, "It's an area of great excitement and buzz in the open-source community. We have customers looking forward to this technology. It will allow them to increase the utilisation of the very powerful dual-core and HyperThreaded servers that will be coming to market later this year." Both AMD and Intel are expected to launch dual-core versions of their respective Opteron and Xeon processors later this year.

Carr said that Red Hat supports its enterprise server software for seven years after release, so its focus is on software stability good management infrastructure.

Unfortunately for proponents of purely open-source systems, it seems the Xen project supports fewer operating systems than the commercial alternatives like those from virtualisation specialist VMware or Microsoft. Xen can only be used to host virtual machines running a few specially honed versions of Linux.

Xen developers say its para-virtualisation technique achieves a performance overhead of just a few percent relative to running on non-virtualised, or native, hardware. Version 2.0, released last November, runs on most modern x86 hardware supported by Linux, and is easy to add to an existing Linux system.