Scalent, SWSoft and Microsoft have all recently introduced new virtualisation systems for the data centre.

SWSoft this week introduced a new version of Virtuozzo for Windows that supports the same features as the company's Linux version. Also this week, Microsoft announced an update to Virtual Server that adds some features and formalises Linux support.

Both are designed to allow multiple instances of a server to run on a single machine, a feature supported in newer hardware from Intel and AMD.

Scalent's Virtual Operating Environment (V/OE), introduced this month, takes a different tack to increase server utilisation, aiming at better managing the commodity servers now filling most data centres. V/OE is designed to deal with the problem of "server sprawl" by allowing administrators to treat heterogeneous servers, networks and storage as a single fabric.

SWSoft's Virtuozzo 3.5 for Windows adds support for AMD and Intel's 64-bit EM64T and AMD64 architectures, something already supported in the Linux version.

The software will allow users to restore single files and to create scheduled backups. It includes improved user resource reporting, and the ability to assign multiple NICs and storage devices to a single Virtual Private Server (VPS).

At a speech at Microsoft's IT Forum in Barcelona on Tuesday, Microsoft senior vice president Bob Muglia said that Virtual Server 2005 R2 has gone to manufacturing and will be released in December.

The product supported Linux before, but this wasn't made official until now, Muglia said. Linux support is important because data centres generally use multiple operating systems.

The release will add failover of a virtual operating system session from one host to another in cases of hardware failure. The software will support clustering virtual machines on a single host, clustering over iSCSI and support for 64-bit Windows.

Scalent's V/OE claims users can as much as triple their server utilisation. The system is somewhat similar to the concept of network attached storage (NAS), allowing applications to treat physical infrastructure as a virtualised fabric, Scalent said. V/OE automatically re-allocates resources to the applications that need them.

"IT management can not only see an immediate and dramatic increase in the utilisation of the servers they already have, but now they can manage their longer-term server provisioning in an effective way," said Scalent chief executive Ben Linder, in a statement.

The software installs without disrupting existing processes and works with all popular servers, switches and storage, the company said. Supported operating systems include Red Hat Linux, SUSE Linux, Windows 2000, Windows Server 2003 and Windows XP.